I understand you. Sometimes alignment can be nuanced. More often then not though its pretty clear cut.

Abominations liking to eat sentient humanoids (often times preferring humans) is pretty clear cut for why theyre evil. Same goes for Drow and Orcs honestly when you look in the lore how their societies work.

Some things have changed over the years though like how things sometimes were evil by nature but now beeing changed to not always be by nature but by nurture. Given that dnd has been around for a few decades its bound to happen that some things change over time.