The post I was replying to had suggested that female Dwarves would need to have breasts in the same way human women do (permanently, in other words). The answer is that no, *that* was an assumption and there's no reason they should, because it doesn't work like that among our fellow mammals, not even our near relatives among the great apes. So even if Dwarves were 100% real, there'd be no reason why Dwarf-women should have breasts except when they're pregnant or lactating and the rest of the time they could be flat-chested, making it all the more believable that they could be as indistinguishable as they were said to be. People tend to downplay it because it doesn't suit them, so they look for reasons it couldn't work - well, that's one less.
You're downplaying it yourself, it's not just that they looked male but that they sounded that way too. The resemblance was meant to be a lot closer than you've allowed for there; certainly we should go by what Tolkien said but take full account of it and don't just look for reasons to shoehorn in something more conventional.
"For the Naugrim have beards from the beginning of their lives, male and female alike; nor indeed can their womenkind be discerned by those of other race, be it in feature or in gait or in voice, nor in any wise save this: that they go not to war, and seldom save at direst need issue from their deep bowers and halls."
- HoME vol. 11