Real kung Fu was not made for a sporting event.
I think this is a bit of the "no true Scotsman" fallacy.
Kung Fu has been used for sporting events for a very long time, in a much more dangerous environment then MMA. Do a little search into "Lei Tai".
Nowadays Sanshou is quite popular, and still uses the Lei Tai, but the sport has been made safer through rules and equipment.
There are people who train in iron palm who can break 7 bricks free standing with no spacers, why would they join a fight where they have to cover up their hands?
Breaking bricks and fighting are two very different activities, and they will draw different sorts of people too them.
Wing Chun concentrates on strikes to vital areas that MMA events dont allow, so why the hate for the WC guys who go into the cage under rules they are not used to following?
Not too long ago all those rules didn't exist, and a couple guys did try to compete. It didn't work out well for them though, Wing chun training simply doesn't translate well into MMA fighting.
No need to get defensive about that though, MMA training does not translate well into wing chun fighting, chi sau and other things. We do different things, and have different objectives, which results in different skill sets.
There is so much disrespect from MMA people trying to discredit real martial artists because they wont fight in MMA.
Have to admit, I don't see much of that. Even among the folks you are seeing the majority of the time I've seen anyone make those sorts of claims is when someone claims their style, which doesn't compete, would easily win if it did compete, except that their style is "above competition" and "too dangerous."
Which is silly, it's like me claiming I "could" beat you at Chi sau, but I don't want to, because I might hurt you.
If you don't train for MMA fighting, you are not going to do well at it, I don't think anyone expects it to be any different. Well, ok, some people might give you a hard time about it, but it goes both ways, there are also Wing Chun people that claim Wing Chun would mop the floor in the cage, except no one will fight because of some silly reason.