Looks to me like you have it backwards. Both the Democrats and Republicans are right wing parties. Even "socialist" Obama is a moderate right winger in his policies. So far as Canada is concerned the Conservatives are moderate right wing and the Liberals centre left. Vote splitting in Canada usually occurs on the left with the NDP, Liberals, and Greens sharing the vote. There really aren't any viable right wing parties to pull votes away from the Conservatives. Fortunately, most Canadians simply have the good sense not to vote for them most of the time.
Actually he may not be right on but he's not as far off as you say. CANADA has slid progressively to the left ever since the second world war to a point where most Canadians have no idea where we sit on the ideological scales (as evidenced by the self delusional ramblings of SJP and others here). Calling someone like Obama, who does champion programs like gov't run universal healthcare, more gov't involvement and regulation in the private sectors, etc. a mild right winger shows how skewed the Canadian definitions of left and right are.
As for the vote splitting argument, there is some truth on both sides. Presently there is some splitting on the extreme left with the rise of the Greens to compete with NDP and the left fringe of the Liberals. The "center" (more correctly center left) sways back and forth between Liberals and Consevatives. The center and center right gravitate to the Conservatives because there is no where else for them to go, while the extreme right is isolated into little fringe pockets like the Christian Heritage Party. If you go back a decade, before the PCs and Reforms merged, the primary reason Chretien won his majorities is because there was a split on the "right", not because he and his politicies were overwhelmingly popular.
As for the claim of Trudeau being the most beloved PM ever, I've seen some polls from places like the Dominion Institute on that subject and there is a stark regional variance (the West and Quebec having no great love for him, Ontario being the reverse). If I recall correctly he is one of, if not the most popular PM according to the polls but his popularity never approaches 50% of the country never mind 70%. There are also polls that show Trudeau as also being far and away the most hated PM. The most accurate conclusion is that he was probably the most polarizing PM in our history... which is at stark odds with the claim that his biographers and Liberals make that he sought to unite the country...