Blocking here is simply a way to remove annoyances from your sight, nothing else.
If you need to prevent them from repeatedly contacting you, or spreading bullshit against you, or something similar, contact instance admins instead. They're the ones responsible for keeping users safe.
Isn't the way it works now also a debate winner? The blocked user can reply to you and you won't even know, so you can't refute whatever they've said (and if you've blocked them there's decent odds it isn't good).
Apparently this is how blocking works over here. It doesn't make the blocked user unable to interact with you. It just makes them scream into a void. I think the idea is that if you block someone they disappear from your posts but not the other way around.
Don't let that bug you. They are no longer taking up your time and energy, and that's what matters. If they are an asshole, chances are high that others are blocking them anyway.