The Taliban are no angels. They do have a terrible track record wrt human rights and terrorism during their first rule of Afghanistan.
Having said that. There is nothing much that China can do about the Taliban other than engaging with them. I mean what are the alternatives? There is the ex-Afghan govt who is pro-India, anti-Pakistan, and in extension anti-China. There is the Northern Alliance who are no different in ideology and savagery to the Taliban. And finally there are ISIS-K and Al-Qaeda; big no-no's. Ideally, Afghanistan should return to the old secular, socialist government prior to the Mujahideen uprising. But that doesn't look even remotely possible right now.
Sums it up perfectly. No one likes the Taliban, but everyone likes the idea of wading into yet another "regime change" quagmire even less.