Do any actual evolutionary scientists believe that humans stopped evolving at any point?
HIV alone is a direct example - many people world wide have died from this, but a small handful of people have been found to be resistant to it.
A classic (and sad) example of evolution at work.
A similar thing happened to North & South America when Europeans showed up with dozens of new diseases, wiping out a large percentage of the native population. (See "Guns Germs & Steel - an excellent read)