This does not just happen in Kung Fu, but other arts as well. I have seen both Karate and Taekwondo schools pull this same hocus pocus act and say how such and such style is not as good and this can counter this and blah, blah, blah. Guess what, there are only so many ways to punch, kick, elbow, and knee. And even though grappling arts can differ they share just as many similarities, which is why under an agreed upon ruleset you get many different competitors in grappling tournies.
Sure there are bad Kung Fu schools, we all know that, we have all argued about it a zillion times, why not focus on the good stuff and let the crap be crap!
"The hero and the coward both feel the same thing, but the hero projects his fear onto his opponent while the coward runs. 'Fear'. It's the same thing, but it's what you do with it that matters". -Cus D'Amato