Don't think that'd work. Traditional practices and attitudes are a sacred category in this sort of discourse, but that doesn't mean they're unassailable -- it just means that any sufficiently inconvenient ones get dismissed as outliers or distortions or fabrications rather than being attacked directly. It helps, of course, that in this case they'd actually be fabrications.
Focusing on feelings is the right way to go, though. This probably needs more refinement, but I think you should do something along the lines of saying that exercise makes you feel happier and more capable (which happens to be true, at least for me), and that bringing tangible consequences into the picture helps people escape middle-class patriarchal white Western consumer culture's relentless focus on immediate short-term gratification (true from a certain point of view, although not a framing I'd normally use). After that you can talk about how traditional cultures are less sedentary, but don't make membership claims and do not mention outcomes. You're not torturing yourself to meet racist, sexist expectations of health and fitness; you're meeting spiritual, mental, and incidentally physical needs that the establishment's conditioned you to neglect. The shock is a reminder of what they've stolen from you.
You'll probably still get accusations of internalized kyriarchy that way, but it ought to at least be controversial, and it won't get you accused of mansplaining.
I think this is still too logical to work. Each step of an argument is another place that can be attacked. And because attacks are allowed to be illogical, even the most logical step has maybe 50% chance of breaking the chain. The shortest, and therefore the most powerful argument, is simply "X offends me!" (But to use this argument, you must belong to a group whose feelings are included in the social justice utility function.)
Now that I think about it, this probably explains why in this kind of debates you never get an explanation, only an angry...
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