"By pushing for a coalition at the worst possible time you risk creating a precedent that coalition government in Canada is illegitimate.
That assumes that the coalition will do a miserable job governing. It also assumes that the poll numbers remain the same, tomorrow, and for the foreseeable future. It also ignores the fact that the results of the last election gives the coalition legitimacy.
Now your point about risking an early election is a valid one. But it has nothing to do with the legitimacy of the coalition.