Taiwan is supplied with weapons. US and Taiwanese gov't officials take Xi's threats quite seriously. No need for legitimate cover.
https://www.nytimes.com/2019/06/06/us/politics/trump-taiwan-...
https://www.nytimes.com/2019/06/06/us/politics/trump-taiwan-...
It is. But re-integration remains a goal for Beijing. If not realistically, then at least politically.
The more aggressive Xi has been with Hong Kong, the more Taiwan has stiffened. Rolling tanks into Hong Kong would give Taiwan legitimate cover for being supplied weapons. For a variety of reasons, China doesn’t want that. That, in turn, gives the protesters leverage.