Sadly the guys I play with regularly don't really play heroic characters (they're not ACTIVELY trying to play bad people, they'll just basically follow the lead a DM gives them), they'd absolutely go along with helping to colonize an area. Heck, the area doesn't need evil races like orcs and goblins, if I put in wood elves or dwarves but they're not designed as part of a story to get the good guys to switch sides, they'll just go along with it. Unless I actively spell it out that they're supposed to be switching sides, they'll sign up as concentration camp guards and just as part of procedure will shoot down civilians trying to flee and will take it as an intended investigative challenge to root out fantasy equivalent Schindler.

I mean I say they're not actively trying to be bad, but I recall one guy at the table who, when an NPC withheld letters intended for the party in return for them wooing a woman he liked, the guy got angry and tried to find the woman first saying he wanted to scar her to punish the other guy; he compared it to when a child is being a brat and you break his game disc to teach him a lesson. I'm happy to say at least everyone at the table was stunned rather than agree.