Of course the Jewish parts of Toronto and (I think to a lesser extent, but certainly Mount Royal fits) Montreal are amongst the most affluent - and in a comfortable suburban sense - parts of the city in question. So what if one or two of their grandparents voted Communist?
Which would explain why Orthodox Jews voted for NDP. Well, that's supposing than the person who said that was right, but I have no reason to doubt an NDP organizer about that.
That would make sense because they aren't rich, many are even quite poor.