They are not being pedantic here, they are establishing a meaningful difference in words to help distinguish a shared phenomena. I think the original comment was unnecessary and certainly bigoted, but I would need more to say racism. The "grammar" guy clarified twice the semantic difference they personally observed (note they did not labor on syntax like you wish to suggest).
All that said, I make this comment as I believe the other commenter's worry is on display im this comment here...
> Again you seem more concerned with grammar than, y'know, condemning racism, prejudice, or bigotry. They're all equally bad and closely related concepts
These are _not_ all equally bad. Prejudice is foundational to understanding, there is no escape from this. In this understanding, we should treat particular postures of prejudice more serious than collapsing any "bad prejudice" under the same label.
All that said, I make this comment as I believe the other commenter's worry is on display im this comment here...
> Again you seem more concerned with grammar than, y'know, condemning racism, prejudice, or bigotry. They're all equally bad and closely related concepts
These are _not_ all equally bad. Prejudice is foundational to understanding, there is no escape from this. In this understanding, we should treat particular postures of prejudice more serious than collapsing any "bad prejudice" under the same label.