You can certainly judge their actions.
- Everyone has intuitions and hunches about people's character that stems from observation that may or may not be true, but what good comes from judging someone?
- Even if someone is acting hypocritically what good does it do in declaring it?
The truth is we are called to love our neighbor regardless of whether or not we like him; and we don't always know a person's heart or the hidden circumstances under which they act.
Hence, we are called to judge acts, but not persons. Acts can be judged as right or wrong, good or evil, but only God knows the true degree of guilt any individual has.
The rule of thumb is to love the sinner and hate the sin.