Scrimp certainly. My son benefits from being in a family environment where he understands boundaries and hears feminist conversation all the time - it informs his attitude towards all women, towards other men, and he has a sense of security in his own self by not being bound to gendered thinking, insofar as that is possible in our culture.
But women's rights aren't about the benefits to him, they are about his sisters. The system will already work for him in many ways - his sisters have been intimidated while out walking the dog twice in the last month and spent an evening afterwards looking for reassurance that they did nothing wrong.
It's just a focus thing, imo. Bottom line for me - 'including' male trans people's voices, however sympathetic, could mean a woman with a male trans partner might feel pushed out of a conversation about her rights. I just can't do that, however effective it might be at convincing fence dwellers. My feminism wouldn't be worth shit if I was knowingly excluding women like that.