My two cents
I think it is the result of many different factors. the first and most obvious is the “my style is better than their’s” attitude. Definately a killer in multi-culturalism.
But I think there are other factors which is just as devastating that makes japanese practitioners become anti-chinese MA.
First, wushu and the unobvious nature of kungfu forms.
Now, we know how the performance wushu are like. And we are very clear on distunguishing between them. However, as far as the non-chiense practitioners are concerned, they are all just CMA. Nothing different. Hence, by relating kung fu with performance wushu, they find CMA nothing much flashy, unusful moves.
Also, if you look at our forms, to an outsider’s point of view, they are very “flashy”. Or as least, the meanings behind them are no obvious. Does anyone still remember their first lesson ? And how we kept wondering " what the heck am I doing ? " In JMA katas, their the meanings of their moves are shown. A kick is a kick, a punch is a punch. but for CMA, things ain’t like that. Without this reference to their own style, they have no other conclusion but to state that they have no meaning at all.
Another thing. people tend to see kung fu as one style. Like karate. this kind of… degrading of status makes it less imposing in the mind.
There seems to be a somewhat “fix” concept of what “fighting” is. the straight punch, hook kick, wrestling, ideas seems to be quite hardwired into the common people’s minds. Together with reinforcements from training in that direction, people take it as the fundamental core of fighting. As long as this is satisfied, everything else is open to disuccsion. Now, if you demonstrate a CLF Sau quan, or a Mantis Dui sou, it has little resemblence with the fundamental core. hence, being classified as being “non correct” fighting techniques. Because it is not correct, it is of a lower form.
Actaully, i have plenty more. But I get the feeling what I have put down is already going to give rise to come controvasy. hence, I end it here.