Available evidence does not support Alexandre Bissonnette's having been a PQ supporter since the age of 15, which is when Jacques Parizeau made his boozy statement.  A statement which was supported by nobody, and led directly to Parizeau resigning his position and being largely persona non grata both in Quebec and within the PQ.

Trumps's statements about muslims, however, were made within the year before the killings, and received huge publicity, including in Quebec.  Of course, there are some who have blamed Justin Trudeau for it.