Blocking a user so you no longer see their posts is a long established feature of various web forums, chat systems, and comment sections. I do not know how you would come under the impression that the reverse is true; the only platforms I know of where it is, is the four or five social media giants. People do complain about Discord blocks, but they complain about them because there is still a 'N blocked messages' indicator, not because of what direction the blocks go.
Discord gets to move fast at some expense to the users, but mostly those users do not care, as long as messaging/voice chat functionality isn’t impacted.
Not sure what point you're making here. The equivalent of a "block" that goes the other way is kicking or banning the user. That works the same on IRC.
Discord is a company that seems to just fly by the seat of their pants. A great example would be "threads", for which they rolled out with no notice to server admins - it just suddenly appeared - and worse, threads were rolled out before thread-related roles were.
Even worse: threads created before the roles were updated to include thread roles could not be deleted by server admins/moderators.
The mind boggles that such a large company, presumably full of very qualified and well paid engineers (and likely piles of "UX" people) could generate such a clusterfuck.
Another great "feature" of discord: blocking someone, unlike every other platform save IRC, does not hide your content from them. It hides them from you.