The thing is there are so many attackers/rookies out there. I wouldn't call them hacker as they are most likely noob running scripts to scan the network. Just seconds after I exposed my server's SSH port, there were failed login attempts. I wasn't worried about someone breaking in as I've harden my server with all the patches, no password login allowed and the private key was on a YubiKey which I don't have it myself. So unless there was a 0-day I haven't patched, it's very unlikely someone else can actually gain access to it. From the logs I could see lots of failed logins using various user names/passwords most likely using a dictionary. Those nonsense soon flooded my logs and I eventually had to change the SSH port as I could not stand that any longer.

As you mentioned, simply ban couldn't help less. But anyway, their servers, their choices. I've no comment on that.