Historically, the name came from Dave Nichol, who was president of the company for decades. He actually had a very strong hand in the selection of products that were included in the product line.
Apparently all kinds of people would pitch product ideas at him, and would taste test them and pick only ones he liked. The idea of "President's Choice" wasn't to be cheapo no name products, but unique and distinctive stuff personally picked by the company's president.
And Dave wasn't just some guy in the corner office. In his prime he was a Canadian personality, and you saw him in TV commercials. Once he left Loblaws in the '90s the President's Choice stuff lost its panache and meaning.
It's just as much a sport as figure skating or synchronised swimming.