With respect, actually it does. Androgen blockers and the lack of testosterone depleted the bone density in males (and mtf women transitioning).

See https://www.webmd.com/osteoporosis/features/male-men#1

The most common cause of male osteoporosis is testosterone deficiency, says Mystkowski. "There's a clear consensus that when you're evaluating men with osteoporosis, you always evaluate for testosterone deficiency," he says.

For low-testosterone men, doctors may advise testosterone replacement to build bone mass. The dilemma is that science hasn't yet shown how much of the bone-building benefit is a direct testosterone effect -- or the result of turning testosterone into estrogen. "Probably the bulk of the benefit is the testosterone," Mystkowski says, "but it's important not to minimize the role of testosterone to estrogen conversion."

And as you already know, trans women need to block their testosterone and take estrogen in order to chemically transition.

That article from WebMD is focusing on men and male bone density. But your hypothesis is that trans women have an unfair advantage due to them being born male and maintain their male bone density. But as you see from the WebMD article, cis men are quite prone and susceptible to osteoporosis and osteoporenia due to low or lacking testosterone.

Those are the same factors that trans women seek.

The argument doesn't hold water.