the point is that those frustrated "anti-everybody voters" are probably mostly not conservatives.
first off, if they were, they'd tell pollsters that. they're not doing that. second, when you compare to recent elections - the fact is that the conservatives have struggled to get over 25% in quebec since the meech lake accords - they're clearly recent ndp and bloc voters, as both parties have taken huge hits.
at this point, if they were going to vote liberal, they'd probably just admit it. but, the fact is that they've avoided voting liberal for this long because they actually don't want to do that. canada is not a two-party system - there are many, many people that are fundamentally to the left of the liberals, base their entire identity on that fact and will never, ever vote for them. in quebec, 23% is probably an underestimate of this type of voter.
so, it's hard to believe they're going to vote for the conservatives all of a sudden. and, it's not much easier to believe that they'll vote for the liberals. likewise, maxime bernier is not likely to do well amongst this group of people - not for his views on immigration, but for his economic views. these people are leftists.
more believable is that they'll stay home.