Again it only plays into the hands of people looking to persecute incels to cheer on, advocate or joke about ERs.
Yeah that put sites like this on the map but in a bad way and now communities like this are being used to bring down men's rights groups that can potentially make things better in the future by associating men's rights groups with incel terrorist attacks.
If there is another ER attack do what the manosphere did previously that worked for them:
don't cheer it on, don't talk about it, don't encourage more things like that to happen.
Don't give them more things to point to on sites like this that encourage the idea that incels are terrorists.
Because whether you like it or not that's the way the world is now and there are people looking for moments like that to seize upon "dangerous" or "violent" rhetoric to prosecute all incels and shut down all incel communities.