Yeah these won't be more than 50 tbh
Bots are quick to get banned so no point in blacklisting them because by tomorrow the bot who will spam in the chat is going to be another one.
People, who spam things like what? Most are by incidents from what I see.
FCs recruiters aren't that many. Their messages are but just blacklist a couple of them and it will all become quiet.
People who harass you should be reported as well as blacklisting but as FCs recruiters they shouldn't be many.
Which in the end doesn't exceeds 50 players unless something is wrong indeed and that's probably from the player's side, not theirs.
It's not useless. Imagine blacklisting all the good players at PvP from the opposite factions so you don't get matched with them?