What predates what, does not imply causation though.
Without the FLQ, and moderate Quebeckers seeing lunatics and murderers, trying to usurpe democratic process, with extreme acts of violence, maybe things may have indeed been different.
But when moderates recall the acts of violent radicals, maybe they think "I'm not sure I want to vote for anything associated...", or "If they thought violence was OK then, what laws may they pass when in power?"
The stigma of the FLQ rubbed off on peaceful separatists for a long time...