Why can't I reply to this specific user's comment?

The title.

Maybe they’ve blocked you.
If so, that’s a piefed-specific feature. People I’ve blocked have definitely responded to me.

I guess then if the person decided to block OP after replying to OP, they could effectively lock in their statement without rebuttal from the person they block. Seems… odd.

Especially here since it’s between two users from the same instance but in a lemmy community. So there could be something going on with compatibility there?