Whether or not a Justice elected by majority is inferior, I have no idea — however, in terms of their administration of Justice, it would present too much of a bias in order for them to render decisions, in my opinion, with consideration of the Constitution and legislative measures, as opposed to what they think the population of Canada thinks the ruling should read.
Justices should not be afraid to make unpopular decisions — they should not have to consider whether or not their decision is going to upset people. For example, in terms of the responses of the Supreme Court of Canada to the same-sex marriage references, they responded in accordance with a widely-accepted interpretation of the Canadian Charter of Rights and Freedoms (not only the Supreme Court of Canada, but a majority of Supreme and Superior Courts of the Provinces and Territories).
:!: Sidenote
Our Supreme Court of Canada consists of Justices appointed by three turkeys, just so you know (soon-to-be four); our current Chief Justice was appointed to the Court by the Right Honourable Brian Mulroney, five current puisne Justices were appointed by the Right Honourable Jean Chrétien, and two were appointed by the Right Honourable Paul Martin — the vacant position is to be appointed by the Right Honourable Stephen Harper in relatively short order.