Subverting expectations with monster races

Hey all. I'm running a RL game right now and I have a conundrum. For context, the PC's are crossing a swamp in order to get to the BBEG's lair and there is a goblin village between the PC's and their goal. What I WANT to have happen is the PC's interact with the goblins, as opposed to what I'm worried they'll do, which is go through and murderhobo their way through said goblins. Now, I don't blame the PC's for this, DND trains players to kill goblins without a thought, but I thought it would be interesting to challenge their core assumptions. How would you guys go about getting your PC's to not attack what is typically a monstrous race?
Right now, I have a true neutral druid (an ettin who has one head that is pro-goblin and one who is pro-human) who is going to broach the subject and encourage them not to attack, but that feels a little heavy handed. Do you guys have any thoughts?

Maybe in their first encounter with the goblins, show them acting intelligently and not monstrous. Have the PCs encounter a group of goblins transporting an injured one. When the PCs approach, they'll put down their weapons and ask to be allowed to continue peacefully.
Or have a group of playing goblin children run into them and run away screaming.

Just some moment to switch their brains from combat mode to social interaction mode.

Show the goblins doing peaceful things, tending a garden, playing with children, building their homes. Include a few other races, maybe a harmless looking person laughing with some of them.

Lastly, don't call to arms and put the PCs on the defensive.

Maybe you could have the goblins be engaged in some activity that "humanizes" them in a significant way? Something that would force the players to rethink the slaughter impulse?

...or teach them with consequences. The first goblin they meet is carrying a trident and net - they approach from behind - it hasn't noticed them.

If they kill the goblin, then you have toddler goblins come running in shouting "Has daddy has caught any fish yet? Mummy says the baby is hungry."

I would be so gutted by this that I would probably quit the game, lol.

Edit to add: When I started typing my original comment, there weren't a bunch of other comments ahead of me saying what mine would say, only better. Sorry for the redundancy!

For me, it would help if you define what your game considers a monstrous race. Do the goblins in your game match the stereotypical evil creatures that many players have experienced, and you just want this particular village to be different? Or are these the first goblins the party has met and you are hoping to establish that goblins can be as varied as humans?

Designing the village itself can also play a role. Undoubtedly a village in the middle of the swamp will have walls to keep out the wildlife, and guards to sound the alarm. I assume the PCs are scouting and would see the village; the goblins should be doing things any agrarian society would need to do to survive. Some might be fishing, some might be cultivating plants, maybe there's even an outdoor school for little goblin kids.

Or perhaps the goblins are celebrating something like a wedding or a harvest festival. There should be music, dancing, feasting, and laughter. No bullying, no pranks, just folks having a nice time and ensuring that everyone is happy.

If the PCs meet a goblin, the goblin is never threatening. Maybe they're happy to see new folks. "Hi! What's your name?" The guards might be wary, but they are polite and will summon the village elder to speak with the PCs.

Others have offered good suggestions. Personally, I'd put the PCs in an immediate moral quandary: Maybe have them stumble upon a small group of goblins, at least one of whom is gravely injured. The other goblins beg them to help save their companion. The PCs will worry that it's a trap, but have the goblins bend over backwards to prove they're sincere (casting away weapons, allowing themselves to be tied up, whatever) -- as long as their buddy gets healed. As this encounter plays out, maybe one of them grumbles about how other races always see them as monsters.

The PC's have actually already encountered the goblins. Spoiler, their first instinct was to attack immediately. Rogue snuck up and sneak attacked them so there is already bad blood. I'm hoping the druid can talk them down a bit. I don't know if it is a plus or a minus that the PC's got wrecked when they tried to attack the main goblin party. (poison plus hide as a free action turns out to be a nasty combo). I'm hoping this will incentivize them to take a less dangerous approach.

Maybe you could establish a common enemy. The next time the PCs fight the goblins, something much worse shows up, some sort of monster, and the goblins offer to stop fighting the PCs and unite their strength against that threat. After that, they can just retreat but it would have shown the PCs that the goblins aren't just enemies, especially if one of the goblins can maybe heal or buff the PCs in that encounter.

You could take a page out of this diskworld book, Snuff, and have the goblins produce something of beauty.

This are all great suggestions :D I’ll add a more twisted one that is not for everyone but could work as an important aspect of the campaign...

Actually your initial thought seems fine since the group has already encountered the goblins and you have an NPC that is protecting the area (I assume that is what he is there for) and helps the goblins as well as other more peaceful races cohabitate then yeah I see him approaching the PCs to determine if they are truly evil or just misguided.

He of course would be strong enough to enforce the rules of his domain against the PCs if they chose to attack, perhaps bring a small contingency of animals and/or goblins to make deal with evil intrusion. Of course, if the players attack they are in for a routing or if suicidal a TPK.

Note one of the things I do in my games is I always warn the players if they are fighting everything they encounter the chances are highly likely they are doing something wrong and that death is on their horizon because I never guarantee that every encounter is survivable and part of adventuring is learning to gauge this -- then again I have a method for giving out XP for every encounter regardless of whether you actually kill the encounter or not because learning to hide from a fearsome dragon is a learning experience assuming your successful and survive.

That said I did this with Orcs a long while ago, Orcs in my campaigns are just barbarians like human barbarians but they look scarier to humans. Of course their belief that strong is good and power is a must does make them susceptible to evil power mongers and as such do have a bad reputation with the other races but then again elves do not like dwarves and dwarves do not like well anything that is not a dwarf actually so prejudices run rampant and greatly depend on the region you are currently in.