There are layers of things going on.
Firstly, don't ever believe a man who says he's a feminist. Male feminists may exist but I've never met one. My DH comes close to being one, but the fact is that he still has his male privilege and he still defaults to believing that his experience is the 'right' experience. When a man tries to tell you about feminism the only sensible reaction is to laugh in his face.
Secondly, feminism isn't about controlling women's lives. Men do that plenty, thanks. As long as it's lawful and you're not hurting anyone, you can do whatever you please. Feminism is not about policing women's choices, it's about understanding why they make those choices and removing the barriers that prevent them from having a genuine range of choices open to them.
Understanding the difficulties with SAHMing is not about 'right' and 'wrong.' It's about examining why, in a situation where a child has two parents, one of them ends up doing all the caring while the other ends up doing all the out-of-home work. In that situation, both parents lose out - one parent is cut off from being personally and financially independent, the other is cut off from being more involved in the day to day raising of their child. It would make far far more sense for society to acknowledge the fact that between the ages of 20 and 40 a large proportion of the population (both women and men) have children. It is a necessary part of keeping the population going and so should be factored in to the working world so that everyone has a chance to both work and look after children as much as suits them.
What actually happens is that having children is seen as an inconvenience brought about by women that interferes with the Real Work done, mainly, by men. So having children is 'accommodated' in a way that makes it clear to women that actually it's a nuisance and a burden. Hence many women are pushed in to SAHMing.
Because in our society paid work is Real and Important and unpaid caring is 'doing nothing,' SAHMs suffer the automatic penalty of becoming less valued by society. Not only that, but she's put in a very precarious financial situation where she is dependent on her spouse and progressively loses value on the job market year on year.
Having children is treated by society as an inconvenience and the women who dedicate their time to raising children are treated as worthless. This is in spite of the fact that if women said 'fuck it,' fit in with the current working culture and just didn't bother having kids the species would come to an end. The future of the human race literally rides upon women giving birth. And yet, it's treated like an annoying hobby that men have to accommodate.
It's all fucked up. That's the issue with SAHMing. Being a SAHM is a choice, yes, but it's a choice made within a fucked up situation, a choice that could seriously disadvantage you, when it absolutely should not. In fact, raising the next generation is the epitome of valuable, surely? If no one did it, we'd be fucked.