Ignoring the tedious "Icky", "Mumsnet brand of feminism" comments which simply illustrate that self-styled "open minded, art culture" people (and once upon a time I was one so I know whereof I speak) are just as prone to lazy stereotypes about people they assume they understand without needing to engage with as anyone else, I actually agree with a fair amount of this post.
I have a lot more time for the grotesque, art form of drag than I do for the mainstream BBC / DQSH version (albeit that like most of the art world it is still infected by the misogynistic belief that women's bodies and everyday lives represent not relatively disempowered individuals doing what they can day by day with the resources that have within the social contructs they have to deal with, but some sort of representation of bourgeois, or in the latest jargon "cis normative" values made flesh that need to be ridiculed and debased).
Similarly, drag's place as part of LGB culture being a F-you to mainstream gender roles and gender culture may be genuinely empowering and laudable from the perspective of the LGB players and audience, but it's still embedded within and informed by the sexism of the wider culture. Drag may play with the stereotypes of mainstream culture but it doesn't really undermine them - it's not saying "this housewife has her own dreams and rich inner life that is a million miles away from how culture constructs her role", it's saying "hahaha look I'm pretending to be a housewife! A housewife! How crazy funny would that be, if Mr I'm So Straightlaced's little wife was actually a gay man? How funny would it be if she was really thinking really dirty thoughts?". Being marginalised doesn't make people immune from enacting their cultures's other prejudices.
I would love to see a new version of mainstream drag emerge from this that was no longer based on female impersonation and sexist tropes but on imagination, fantasy/grotesque characters and costumes. But that is not what has happened, so using art drag as an excuse for sexist mainstream drag does not fly.
Ultimately, you cannot get away from the fact that whatever drag may mean to the men who perform it, when male drag artists perform as "women" they are treating women as a palette of pieces and concepts, a cultural language from which to assemble their art rather than dignifiying us with respect as humans just as complex and worthy as they are.