timing and bad taste.
a shit film that's bland enough not to rile anybody can do huge business around the holiday season (see also: Patch Adams, The Santa Clause series, Cat in the Hat, Meet the Fockers, etc.). And the standards for an acceptable family film is pretty dang lax.
to be fair, I was into crap when I was a kid too. I thought Home Alone 2 was one of the best films ever made at one time, and I couldn't for the life of me understand why those Police Academy flicks didn't get better reviews.