Let’s not denigrate the memory of the brilliant Stephen Hawking without knowing the facts and context please. Let’s not start a witch hunt where there is no evidence of criminal activity.
Anyone could find themselves unknowingly in the company of a criminal / sexual deviant and being famous makes this prospect much more likely as you will meet so many more people.
I imagine celebrities need to be really careful nowadays - doing a lot of due diligence of new friends and professional partnerships. But even so, some people will manage to cover up their secret life.
The rich and famous can’t trust anyone these days, must be really lonely at the top.