The history of Jazz is a complex and rich story. From founding fathers to people who pushed and pulled the boundaries of what Jazz can be.
Jazz can be a lot of things. Many styles, many forms, many musicians. Most people would not consider Kenny G a Jazz musician or even much of a musician. He's more of a showman than a musician. In the world of music styles approaches are different. There is an amazing amount of tolerance and even respect for musicians that take different approaches to success. More respect is given when the person is technically and musically competent of course. So while many may consider Kenny G's wailings bothersome they don't take too much offense and even begrudgingly be happy for his success.
That is until his wailings and warblings go beyond his own realm of cheesy music and tread on the legacy of one of those founding fathers of Jazz.
Pat Metheny on Kenny G is a good read. At first because it's a valid musical critique of Kenny G's music but later because it shows how vehement people can get when certain lines and boundaries are crossed. Stay in your own world and you can have all the excess success you can claim from popular culture. Mess with things that are close to sacred and watch out. People will no longer congratulate you on your success. People will start telling the world what they think of your actual ability.
Not that the opinion of a really talented musician will change Kenny G's success of course. It will however remind me of why I can't stand Kenny G's version of 'music'.