Trudeau, during his lifetime, was actually pretty progressive. In Quebec, he had the wound of the war measures act, but even that only slightly reduced his popularity among the French Canadians (as I'm wont to point out, there were no Snipers in Edmonton during the NEP). As the NDP was still relatively unknown in Quebec (it was seen as a western regional party at the time by Quebecois), a social democratic liberal leader was a good deal for a Quebec that 20 years of quasi-fascism had shifted massively to the left.
The myth of french canadians united against Trudeau is actually pretty recent, there were a few frictions (hell, one of the most nationalist laws in Quebec at the time was passed by a liberal premier and a liberal house), but there was also a lot of respect, grudging or not, in the west outside of Alberta and in Quebec (and that grudging respect extended even to the nationalists - this was ironically one of the things hampering Chretien in Quebec, as it didn't extend to him).
It's easy to make a national myth against someone who is too stiff to object at the revisionism.
In fact, in Quebec, there were quite a few caricatures of party leaders trying to channel Trudeau to break in Quebec (like one of Stockwell day wearing Trudeau's signature cape, hat and gloves and trying to say fuddle duddle). Let's just say the hate is obviously overplayed when your socialist, separatist teachers talk in such admiration about a man who was one of their fiercest political opponent at the time.