Until this email chain, I hadn't seen the Outreachy thread. I must say that I didn't see anything in what Niall wrote that suggested the SFC was engaged in criminal activities. Rather, he suggested that what's acceptable in the US is not acceptable elsewhere and that Boost should definitely steer clear. He used more accusatory and less conciliatory phrasing, to be sure, but I saw nothing outrageous.
What I find is that unless one chooses to interpret the email and posts that one reads in the best possible way, one can find sinister interpretations of most everything one reads. Niall has been guilty of that and is frequently the subject of that issue.
As for the diversity issue, there's nothing about how Boost conducts itself that is discriminatory, that I've ever seen. Societal pressures may well dissuade women, for example, from getting involved with programming, but why is that Boost's problem to solve?
Someone suggested Outreachy, and Niall quickly, and vehemently, disabused the poster of thinking better of the program than he thought right. If others think Niall has it wrong and wishes to defend the program and encourage Boost's participation, they should do so. Instead, it seems others could only complain about how he presented his opinion. The result, it would seem, is to keep Boost out of Outreachy, as Niall intended.