Aside from the ludicrous notion that anyone other than Canada's Native population is truly "old-stock Canadians," there is a certain divisive, chamber-pot snobbery to the term. It's not a celebration of "lineage," it's a wedge. It has no use other than to separate the speaker from others. Without even having to wonder why it was never used in our house, I know that my parents would have considered it vulgar. We are all "old-stock" Canadians, no matter where we're from, or how recently we've arrived.