Yeah, in certain point of View, i believe some of my Characters (tiefling one at very least) would be even able to like them ...
And we can! Wich is good.
Sadly, i can also imagine some of my Characters (for example my Half-Orc Barbarian, or my Drow Warlock) who would certainly not like their actions, their attitude, and their behaviour ...
Problem (for me) is that in such case all you can do is yell at monitor, or ignore it.

Right. My Charlatan Drow Sorcerer is a manipulative jerk who has no problem killing anyone if it means he has an edge. He also has no issue with killing anything that he perceives may cause him harm. If something is a threat, it must be removed. Period. Doesn't matter what it is.
I find it interesting that so many these days love playing "evil" characters but when it comes to truly being evil, they have issues with it. It reminds me of the SNL skit that the Rock did a few years ago. The skit was about an evil villains conference, and the villains were presenting their evil inventions to one another. Death rays, ice rings, contraptions to destroy the moon... The Rock got up in front of everyone and presented a robot that molests children. Every single villain in the conference freaked out. "What kind of monster are you!"
People don't want to be "evil" in video games. Not really. They want to be evil super villain from comic books evil. Frankly, thank God for that! I'd rather Larian leans away from true evil than embraces it.
Still. Again. I have no problem with Larian making kids of any race invincible as long as they don't then put them in situations where they are threatening our characters. I mean, LOTS of video games make certain NPCs invincible. It's not like it's a huge deal if they make children invincible - as long as the children don't pose a threat. Remove from both groups of kids the ability to alert adults and turn them against our party, and I'm good with making them invincible. Oh. And don't have Mirkon able to be killed by the harpies or the player's party. Just have him immediately run away and hide and have the harpies focus on the player's party.