Boilerplate nonsense. They only care about covering their own backs, nothing more. They don't care about preventing money laundering or combating terrorism or any of the other bullshit excuses they use. They care only about their own profits, and they don't care if you are wrongly accused or you lose your coins in the process.

Uphold, like most centralized exchanges, likely simply buy the services of a blockchain analysis company, and that blockchain analysis company tells them which coins are "tainted" and which ones are "clean", which coins to censor and which coins to accept. The reason they can't say any more on the subject is probably because they don't actually know why they are censoring your coins - they've been told to do it and so they will do it without question to protect themselves, and they don't care at all about the user on the other end.