In terms of needing to save oneself from death and having a choice between pig and human flesh, lichora according to the sugya in yoma 83a, that says that one is meant to mitigate the issurim one needs to violate in life threatening circumstances, it should be pashut that one should eat the human, as according to many rishonim there is no explicit lav banning it (the gzaira shava wouldn’t be enough to give malkus) and eating pig is an aseh and lo taase (see Rambam sefer hamitzvos, aseh 149 (also the aseh to not eat human) and lo taase 172). The argument comparing it to marrying a goya vs non religious Jewess is strange, as there, there are obvious detrimental potential outcomes and potential extreme difficulties of tshuva if one were to encourage inter marriage over non religious Jews and this is talking about a willing sinner whom we’d like to keep as close as possible to Torah as opposed to the eating case, where we’re attempting to save a life and the lesser issur becomes muttar. (see Rambam hilchos isuray beeya perek 12 halachos 7 and 8 as well as shu”t rivash siman 425 who mentions derech agav toward the end that the gdolim didn’t close the batay zonos of Jews because if they had then the men would just go to the goyos and the consequences would be detrimental, r”l. In contrast to the rivash, however, see shu”t zichron Yehuda of Rabbi Yehuda the son of the rosh, siman 17 part 2, but see also siman 97 part 1)
