The issur according to rabbi belski is hasagas gvul i believe. Also geneivas daas according to most shitos is machazik tov lechaveiro which has nothing to do with dishonestly obtaining anything. genaivas daas is for example sending someone an invitation to a wedding when you know that they wont come and you dont want them to come but you figure its an easy way to get into their good graces. it is specifically limited to favor it has never been extended to other issues as far as i can tell. if you look in the poskim this seems to be very clear. i have yet to find anyone who holds that it is actually geneiva as there is no possible kinyan of any sort that can be done on intellectual property. the litmus test of “i would never have bought it” is a slippery slope however it is interesting that rav belsky didnt argue with the premise that such a concept is technically ok (albeit intellectually flawed) – if we would be talking hilchos geneiva there is no such svarah at all. dinah dmalchusa according to everyone but rav pam i believe is only by laws the government enforces and the government has not enforced copyright laws on individual downloaders in a while. the rabbonim who are maikal in this area (rav rottenberg in baltimore for example) hold that this is not hasogos gvul. There is a famous chasam sofer on intellectual property which is widely quoted – the rabbonim of the town had to create a special gezeira to prevent people from buying a set of rambam from a non jew who copied the typset from a jew and was undercutting him. It seems that they did
not hold that this was an issue of massig gvul (on the buyers part). This was a special gezeira because they were afraid torah would be lost if people could not make a profit off of printing seforim. I will find the exact mareh makom if people are interested but i think it is readily available online.