As someone that's pretty much up to speed with current 5e lore, I'd honestly never considered that tieflings hanging out were going to be confusing thing for some people. Huh.
Talking to the leader, and some other NPCs I think, reveals why this specific group of tieflings got there and their history and such. No general "Okay so this is how tieflings are regarded in this games universe..." type of thing tho. Considering that you, the player, can be a tiefling it would be pretty weird if an NPC suddenly started to explain your own racial lore to you.
Not sure what the solution to this problem is, but tiefling lore could probably be implemented into the dialogue before you get to the camp. The siblings who capture Lae'Zel could be a perfect opportunity to do some loredumping.
