I have heard IPSC and IDPA shooters bash each others sport. Your'e going to have people doing that, we are human beings.
I'm lucky IMO, the people who run the matches and regulars who shoot at the local IPSC club also shoot at our IDPA matches and we shoot at their matches also. We all seem to get along. Yes we have difference's of opinion, and confusion sometimes with the rules when shooting the different matches, but that is to be expected.
Since IDPA is an organized shooting sport you are going to have people that do it just to compete. You will have others who come out and get frustrated since what they are using they feel hampers them compared to everyone else. That's just the way it's going to be.
Also don't forget the fact that people will many times use what a lot of others do or what the cops carry thinking that is the best tool. A lot of cops carry Glocks nowadays, so a lot of people want to buy and use them. Also, the Glock is simple compared to other auto's, at least in their eyes.
Me, I don't worry about it. One of the biggest reasons I like IDPA is that you have four separate division's. I can shoot my revolver as well as my auto and I don't have to reload an inordinate number of times to shoot an array of targets, let alone a stage.
I still enjoy taking my 625 and a pocket full of moon clips to the local IPSC match. Especially when I beat a few of the auto shooters, even with all those reloads.