There's nothing inherently wrong with gringos choosing to live in Puerto Rico. The problem is the audacity of benefiting from Act 60 and then treating identity as something that follows automatically from residence. Puerto Rican identity isn't an administrative status, it's tied to lived experience and historical context.
Some people in Puerto Rico are apparently upset because I identified as Puerto Rican, despite my having lived here for almost ten years and raised two of my children here. However, had I identified as a Puerto Rican woman, they would have had no problem with my gender identity.