> In past the Chinese government didn't send large numbers of people to camps based on their ethnicity.

In past the Chinese government did send large numbers of people to camps based on their ethnicity.

Tibetans - since 1957

Mongols - since its first years

Miao/Yao - 1982

Koreans - Koreans Chinese were routinely rounded up every time NK-China affairs were flaring up since seventies

And Uighurs were in, and out of concentration/extermination camps many times already in the past. In 1949, 1967, 1976, 1991, 1998