I totally agree with you in most cases, but by many accounts this is a funny movie on purpose rather than finding humor in its unintentional blunders trying to be something else, so it’s only really a “bad movie” in aesthetic. In this case, the veneer of a bad movie is just another tool for making the jokes and a stylistic choice rather than an overall descriptor of any lacking quality in the writing, performance, or technical aspects. Based on that understanding, I would say they actually made a pretty good movie by achieving what they actually set out to make and the movie’s audience enjoying it for its intended purpose.