My understanding is that this "toxicity" is only apparent in western data centres which is why the Japanese based developers have not considered making the existing blacklist option exclude people from being matched and wipe their comments from any chat.

If people are making comments which break the acceptable chat rules (and the incidents you have stated clearly do violate those) then please report them. Yes I know it is a pain to report them especially whilst in a duty. It's almost as if the system is geared against people actually being able to report others in these instances.

Hopefully, if people report this very vocal minority of players the others who thing that such talk makes then big or clever will get the message when the ban hammer eventually falls.