FWIW I don’t think gamblingdudes has anything to do with your site and/or pages being dropped. imho this is totally different than for instance what the captain just experienced, totally!
They havent used your sites name, domain name, or a branded/able slogan, in fact I don’t see anything unique about that combination + ordering of words. A search of the phrase returns dozens of sites using the same structure.
I think your disappearance from the serps is causing you to stretch for an explanation. I havent reviewed the sites in question, but unless they have borrowed more than that specific phrase I dont see anything wrong with it. I would say its total coincidence.