Odd that I'm seeing this brought up as a criticism rather than praise for once but... Yang... isn't butch. That is nowhere even close to how a butch woman looks. The very first Google result for "butch women" is already a great comparison for how she really isn't butch.
Since you're mentioning her having more traditionally "masculine" interests, the word you're looking for is "tomboy." She's a tomboy. She's not butch. I think you're conflating how often the FNDM erroneously calls her butch or makes her actually butch in fanart with how she's actually depicted in the show. That, or you're confused about what "butch" itself means because it's not as simple as "being the man" in a sapphic relationship; a woman having masculine interests does not a butch make, y'know? Yang's interests being more traditionally masculine while Blake's are more traditionally feminine doesn't make one butch and the other femme either. Which is why it's annoying when people praise her for being "butch rep" because she's not. But it's odd to see "RT made her butch" as a criticism in turn because, well, they didn't.
My apologies if I used the wrong terminology. Queer history is still something I'm learning about, being from a very conservative environment.
You're right, Yang isn't a butch. But my whole argument lies in the fact that RT is enforcing really heteronormative traits and dynamic in her queer relationship with Blake, where neither of them were made to be as they are now.
Blake was the more "traditionally" masculine of the two, and Yang was known as the girly party girl. It's very, VERY jarring to see that this dynamic gets swapped seemingly out of nowhere. And from the known record of Miles Luna's fetishization of his ex who voices Blake, Arryn Zech's bisexuality, it comes off really gross.
I can go on for days about how Blake is infantilized. But thank you for the correction.