Considering that it's the speakers sole perogative to recognize individuals in the gallery, this really should start and end with this resignation.
Only the speaker can regonize someone in the gallery, it's formal parliamentary procedure. Trudeau , cabinet, the liberal caucus, the opposition, the rump, and all other MPs would have had absolutely nothing to do with what happened.
To be clear though, I haven't read anything suggesting this wasn't accidental. Like they just saw a Ukrainian vet from WW2 who fought against the Russians and invited him.
It could be a lot fucking worse. I haven't seen any statements put out by any of the political parties in Canada saying "I'm sure there were good people on both sides"...