Jaws 2 (1978) vs Halloween II (1981)

If someone doesn't consider Halloween II canon than how would they be able to consider H20 canon? 

I realize you must be joking because of the contradiction, but I have a hard time telling when you are serious or not.

As for Halloween II being canon, it clearly is. Whether I like it or not is beside the point. The movie is produced and written by John Carpenter and is not only a direct sequel, but takes place the same night as the original.