I mean, I understand why it's a thing in Quebec. I just think it's wrong and, as you say, shameful.
Here's the thing: it's not Quebec thing. It's a rural Canada (including rural Quebec) thing. It's just more visible in Quebec because rural Canada already votes overwhelmingly Conservative so there are no votes to grab there.
Also, that niqab mess isn't going to win the election. Sure, there's a segment of the population (usually one that has no interaction with Muslims whatsoever) for whom the sheer existence of the niqab is worth bitching about. But when they have to chose between slightly annoying some people they'll never meet and actually getting the government they want, they tend to vote for the side that will actually get them something. See also: last Quebec elections, where Charter of Values + the possibility of Yet Another Referendum was crushed by the No-Charter/no-Referendum option.
(and even if it did have the potential to swing some votes, that particular issue peaked way too early.)