A better way to describe this is not that it's federal funding of transgender surgeries, but that it's federal funding of the military. The medical benefits provided to military personnel are part of their compensation package in exchange for their labor and risks. Currently they are allowed to spend this compensation on elective reassignment surgeries. The bill Amash voted against would have banned that when it comes to how they use their medical benefits.
As a thought experiment consider a hypothetical situation where Congress votes on a similar bill, only this version is a ban on allowing military personnel from spending their own money that they got paid for their military service on sex reassignment surgeries. Would a no vote on that still be called supporting federally funded transgender surgeries for the military?
It probably would be better if there were no medical benefits in their compensation packages (or in anyone else's either), and instead the military (and any other employer) just paid its employees more money and left it to them to shop for the insurance of their choice if they wanted. But as it is, including medical insurance in employees' compensation packages is the norm (and indeed, now the law in most cases).
