The only way an "ignore" function could really work would be for there to be a "counter" that would be incremented when ever someone was put on ignore. Then when that counter reached a critical number, the "ignored by many" person would be kicked off of the island, for good, and their IP address noted.
When the troll comes back on with another user name and the same IP address they would be banned for life from registering. If they changed IP addresses the process would have to begin anew.
A certain Troll has shown up in this last week to take the place of the Troll that disappeared a few weeks ago. Of course they are likely one and the same Troll. I would not be surprised that the administration likes the presence of Trolls as they invite much discourse albeit disharmonious discourse. Still clicks are clicks and clicks are good.
I really don't think there is much we can do about Trolls other than as someone else suggested, if you don't like their content, then just use your eyes and brain to scan on to something you do like. The less of us that "take the bait" the less hate and discontent will be generated. I will freely admit I have been "triggered" many times by Trolls, and that is the goal and aim of the Troll in the first place.
If we would all stop quoting Trolls, stop replying to them, stop arguing with them, then they would truly dry up and blow away. No matter where they come from. yeah, I know, easy to say, and not easy to do.