If you take a word that originally meant the mass murder of an entire ethnic group, and then use it to refer to destruction of culture, you're just trying to confuse people. The whole point of calling it the "Uyghur genocide" is to fool people into thinking that China is carrying out mass murder - which is isn't. The retreat to, "I'm talking about cultural genocide" is a bait-and-switch, used once the original accusation of "genocide" is challenged.

Even the accusations of "destruction of culture" are incredibly fuzzy. I think most people who believe in the "genocide" accusation would be very surprised to learn that the Uyghur language is still extensively taught in schools in Xinjiang, and is, in fact, still the primary language of education for most Uyghur children. They might also be surprised to learn that some of China's most popular celebrities are Uyghurs, and that Uyghur culture is actually pretty popular in China.

The "genocide" accusation is simply made in bad faith. One could actually talk about real political repression in Xinjiang, but that would be much less shocking and sensationalist than making up false accusations of "genocide."