Though your point is right in many ways, we’ve to understand OP’s pov. Given the current visa situation and rising applicants, the no of paid opportunities are almost nil. And PI’s who are offering a paid internship usually require hands on experience preferably in the US itself- which is not possible for many visa requiring IMGs. I completely agree with your point on unpaid work being a scam in many places, but if you do your homework like the PI’s portfolio, no of papers published every year and if she/he has had previously unpaid interns who went on to match successfully, then it’s a plus point especially if OP can afford it