Every day, I see absolutely moronic comments getting upvoted while perfectly reasonable takes are downvoted. This would be a great opportunity to curate your feed by blocking these users en masse. Active curation like this is the only way to make social media even half-tolerable.
Whether you use it to filter out toxic users or to build an echo chamber, I think everyone should be free to do so. No one should be forced to share space with people they feel bring no value to the discussion - or, worse, make it more toxic.
I’m not necessarily against that either but personally I couldn’t care less if a blocked person can see my posts and comments. There’s even one commenting on this thread. What I use the feature for is to get them out of my sight. If they want to write me angry comments that I’ll never see, then have at it.