Maybe many of them are just butthurt like what you said but also there are some that have been cheated by gambling sites as we also knew that not all gambling sites operates as how we are seeing and knowing them now because there are other side of each gambling site.
that I also  believe that many of them will try to take players money but when they are being called then things changed and indeed they are paying the taken money from those gamblers sad but reality , while other sites pretend to  be not intended to act such but deep inside its their tactics to take fund from those who have no capacity to run against their behavior .