They're torturing millions of Muslims in Xinjiang, directly or indirectly through terrifying police state actions that entirely revoke all human liberty.
There is no greater mass atrocity going on anywhere on earth than what's happening in Xinjiang.
How many people, companies, VC firms in Silicon Valley are working with China and living off of Chinese money?
Where's the mass outrage and suspension of relations with China? Nope, you won't see that. No chance in hell.
The millions of Muslims in China being tortured don't matter, and one journalist does? Not exactly: it's because China is a big fat platter of money and many want to feast on it. It's a willingness to disregard all ethics because the check is big enough. It's so much money, the people that claim to care about a single journalist, don't care about millions of people being actively repressed and tortured.
It goes to the line about a million deaths being a statistic, and one death being a tragedy. Same premise at work.
Despite being repeated often, to my knowledge there's no evidence for that. It also doesn't sound very plausible as only about 10M Uigurs and Kasachs live there (those two are the mostly muslim minorities living there). If we assume this is about young to middle age male adults (because this is the relevant cohort in practically every violent conflict), "millions" of these are getting imprisoned and tortured implies that a whopping 100% of non-elderly muslim males in the region are in internment camps. Actually more than 100%, if we assume not every Uigur is a Muslim.
What we do know though, is that the conflicts in the region are very violent. Islamic extremists have bombed civilians on multiple occasions, including public markets, buses, killing sleeping workers in coal mines etc. 
And we know the Chinese police has killed people at riots, though I haven't yet researched the circumstances.
In both cases the violence is abhorrent and to be condemned. The mass torturing story seems to be fake, though.