If you don’t have sources, why are you engaging in debate?
I don’t think China is straight up doing death camps. They have put them in "re-education centers" and there has been a significant drop in Uyghur birth rates.
The fact that Islamic countries haven’t spoken out could well be that they are also known for religious persecution. Turkey spoke out against China's treatment of Muslims in 2009 and got hit for it. To this day, China reminds them not to mention it. There’s a lot of money moving there plus the belts and roads initiative.
It’s not clear cut. We can’t definitively say that they aren’t abusing human rights. So, maybe we don’t make claims we can’t prove either?
Edit: I forgot to say it works both ways. If they’re making a claim, it should be on them to provide evidence too. So, ask for that.
Edit #2: or take advice from here and use straw man arguments, whataboutisms, and generally attack anyone that doesn’t 100% line up with your opinion.