Abstracting from this particular case, I imagine it could help to have an additional IRC channel, named e.g. #raku-debate. Something like this surely has been considered before, but I think the advantages are really significant.

The purpose would not, of course, be to say: "Anything contentious must go in #raku-debate and has no place in #raku". It would be a last resort; #raku would continue to be the default place for discussions. But when someone does want to discuss something that others find (in principle or merely at the time) excessively bothersome for the general-purpose channel #raku, then one can say: "please don't discuss this in this channel," and still offer this IRC discussion a place inside the official realms of the Raku community.

It would make it easier on the person who is being told not to discuss their topic in #raku.

It would make it easier on those moderating #raku.

It would also make it easier for people who may have something useful to say on the topic, but decide against chiming in out of concern for others in #raku who are already exhausted by the discussion. Heck, I would bet that at times even simple clarification questions don't get asked for such reasons; which would mean that certain misunderstandings may persist and cause damage when they could have been resolved...