Ohh. Right, that drop menu.
I really haven't needed to blacklist anyone. The accounts will be deleted/banned and remade instantly. For those with legit names, they're undoubtedly stolen or made from a Chinese bot farm.
Though I sympathize with being annoyed with spammers, it's a fruitless feeling endeavor. I have long since learned to mentally block the spamming. Be annoyed as much as you want. It will never stop, barring some insanely draconian efforts by SE, or a whitelist; but then, you'd have the same problem but in reverse.
For a game that won't let you invite people into dungeons unless they are already in the same zone as you or on your friends list (same-realm only!), or a God-hand-Duty-Finder-level-coordination attempt, a whitelist would be even more intolerable in practice.
Alternatively, put the chat in "combat log" only, because a game involving people should be played trying to avoid said people. yeaaaaaaaaaaaaaaaaa