It's nice and all to say you should get retributed for your hard work (and I do think there is an added value here), but you cannot capitalize on someone else work if that someone does not allow it to begin with. You have to accept you worked for free.
Again if a single addon is licensed and specifically mention how it can and cannot be distributed and whether it is allowed or not to ask for royalties, then yes this is a legal issue. I do not have the time to go through the whole MazzleUI pack to check the addons and there may (probably) be no problem.
Forgot to mention this would be within US laws, of course if Mazzle site happens to be located on some Pacific Atoll, then be it
