I most certainly think there is a relationship between the electoral system and the chance of a radical-right party gaining ground. It's not the only explanation. Look at what happened in Britain. It has a similar system as we have, and we've seen radical parties there under specific circumstances.
That said, I think it does increase the chance of having a radical-right party. Whether that would happen in Canada or not is of course an open question. It depends on the sentiments that are there in the population. But who knows what those sentiments might be in 10 years, 15 years?