What do you do, if you can't buy the tickets from the legit sources for whatever reason, then you have little choice?
I very much doubt if Mozza (or any other artist for that matter) really cares, it doesn't affect them at all. The venue aren't bothered because they have already sold the tickets so have made their money.
Personally I think the practise should be stopped but how if no one cares apart from the fans who wants the tickets.