The comment saw a story in which the woman did contribute, and rather than discuss that jumped to a hypothetical in which a "spouse" did not contribute.

It is valid to ask if this shift from talking about the actual story to talking about invented hypotheticals, and hinting at the danger a spouse might pose to one's company, would have been as quick or as easy or as likely had the spouse in question been male.

And the reason that people always "bring gender into it" or in other cases always "bring race into it" is simple: although to you it may seem that these factors are completely unrelated, to other people the whole experience of their lives is of gender/race being forced on them as a factor. The lack of that experience on the part of a minority of the population (white men, mostly) is not equivalent to gender/race not already being "brought into it", but rather an indicator of the ways in which biases and double standards, once deeply-enough embedded into a society, cease to be seen as such and instead are assumed to just be the default neutral state of affairs.