That's a freedom of association argument, and it's valid up to a point. This case goes far beyond that point..
Where did I say "freedom of association"?
Individual freedom of thoughts and expression was presented in three points-of-views vantage-points in this specific scenario: (1) the male student requesting religious consideration, (2) the instructor consider the dojo context, personalities, and politics, and (3) the female student who took it personally and took offense on possible sexist issues.
Perhaps all are correct given their own personal perspective. No matter what decision the instructor makes, he loses some one. He made a personal judgment call to respect a religious request. That is between them. The offense taken is between the instructor and that student.
Perhaps if freedom of thought and expression means I have to limit my association (touch) with certain people, right or wrong (just meaning you agree or don't) according to others (or me), isn't that within their right as long as it does not cause harm to others?
Who caused the offense taken, the student's request to have his religious beliefs respected, the instructor who respected the request, or the student who took some one's religious request as a personal statement about them?
"Up to a point"? Absolutely!!! If he came in and requested to touch/workout with only young girls or women - well we would be having a whole different discussion if I were the Sensei.
Appreciation the discussion.