And that's why I think paladins are so stupid. Another lore question. How favourably your (supposedly) good aligned God will look upon your extermination of the druid grove?
You still don't get it. It doesn't matter if it's smart or stupid. What matters is whether it's immersive and authentic or not. Tieflings by and large are an overwhelmingly alien and in fact less then good race. The only difference between them and goblins is that they are a bit smarter and you like how they look. That's it.
presumably Tieflings have been a part of the FR world for centuries, you're characterization isn't really informed by immersion but by your own meta-narrative perspective. Even fiends and devils in FR don't typically have horns and red skin, this is actually more of an indictment of WotC for condensing their own mythology into a race with a few uniform features.
Well, the fourth edition is to blame for the tieflings looking like a "horned red devil". There it is justified by the fact that tieflings come from a group of people who have concluded an agreement with Asmodeus. And in this case, their appearance is justified. As for the fifth edition, I still don't understand how the tiefling of Asmodeus, Levistus and tanar'ri tiefling could look the same in rulebook pictures.