You can visit North Korea and never see their work camps either.

Firstly, there is much more restriction on tourist movement in the DPRK for a litany of reasons, mostly pertaining to national security. Tourists in Xinjiang can move pretty freely, though if they are going all over the place they will cumulatively need to pass through many checkpoints.

Secondly, “work camps” here is what people call prison labor in Bad Country. The DPRK has prisons, certainly, and we can have discussions about penal labor, but it’s much less notable than people pretend and much less secretive as well.

Thirdly, “work camps” are not remotely comparable to committing genocide against one tenth of the entire population of the region, which is the claim that was popularly made against Xinjiang before it got walked back to “cultural genocide”.