I traveled around Xinjiang in 2010. I was in Urumqi during the one year anniversary of the 2009 Urumqi riots and there was some tensions. Armored and armed guard units were walking the streets, and the Uyghur people we talked with were very nervous. There was segregation at a business level there. The main strip for food was Uyghur on one side, Hon on the other. At the time, it seemed unsettling, but people were getting on with their lives.
Looking back on it, I realize I was part of a joined agenda. We stayed in a Military hotel, and had a driver/escort who was special forces. We had to get permission to do the things we did. We wanted to stay with a Kazakh family, but were denied and told that we could stay with another Kazakh family. It was all pretty wild, and my friend kept in touch with a Uyghur we met, and she desperately wanted out of Xinjiang... and was essentially living in fear.
I didn't hear about camps then, but I wouldn't put it past the government.
The injection fears, at least, are known to be just standard fear mongering and rumor during the riots, see:
Fear pervaded Urumqi; A week after the riots, stories started to spread that Uighur, or Han, depending on which side you talked to, were injecting AIDS-infected blood into random strangers in crowds. It was an old urban myth, the source of an outbreak of panic in Beijing and Tianjin in 2002, but tinged with ethnic hatred. Thousands of people queued up for HIV tests at local hospitals.
As for stabbings, ya, knives are used for murder in China. The Kunming train station stabbings were absolutely horrible, but so were the multiple kindergarden stabbings that didn't involve Uighurs at all.
Looking back on it, I realize I was part of a joined agenda. We stayed in a Military hotel, and had a driver/escort who was special forces. We had to get permission to do the things we did. We wanted to stay with a Kazakh family, but were denied and told that we could stay with another Kazakh family. It was all pretty wild, and my friend kept in touch with a Uyghur we met, and she desperately wanted out of Xinjiang... and was essentially living in fear.
I didn't hear about camps then, but I wouldn't put it past the government.