But you seem to be thinking that every criticism of her is bound to be racist.
I really don't I was one of her biggest critics until after she left, and have criticised loads of stuff about her here.
I don't think all criticism of her is racist. Only that a) the criticism of certain publications (which has clearly crossed the line from criticism to outright obsession, and is deeply hypocritical) is rooted at least part in racism.
And that b) from what I've personally witnessed over two years of posting in royal threads, which is literally hundreds of threads deleted for overt racism and non-stop lies and bullying, continual racist abuse of black and biracial posters, including very nasty incidents and comments which have happened off-board, and the fact that at least a few of the most fervent anti-Meghan posters have posted so many inflammatory comments on threads about other subjects like BLM, the diversity dance, etc. etc. etc it's led to them being widely perceived as being racist.
Based on all these things, in my opinion it's undeniable that some of the Meghan-haters are plain and simple straight up racists, some of them hate Meghan for a variety of reasons race being just one, and that some aren't actively racist but are being influenced by covert or subconscious racism.
I'm not the only poster who's observed that when a Mumsnetter publicly announces that they are POC, the level of hostility and abuse immediately jumps off the charts when their posting style and content has not changed at all. I know two Mumsnetters who operate two separate usernames, one they use to be "out" as being black, and one where they post in exactly the same way, but simply don't mention that they are black. Both report that their 'black' username is regularly treated with hostility even when they are posting on completely innocuous threads like what's for tea, and any attempt to post about racial issues even in the mildest politest way leads to abuse, fury and harassment. While if those same women post much angrier and more confrontational posts under their "presumed white" usernames, they might get disagreement but won't get personal abuse or rage.