There are topics that a person might want to post anonymously, out of a natural embarrassment, or sense of decency.
But embarrassment can ALSO happen when you're ashamed of what you're doing -- because you know it's wrong.
So wanting to post anonymously is not, in itself, a bad thing -- it depends on whence the embarrassment (or desire for privacy) comes.
But using the Anonymous subforum to talk about people and say things you're afraid to say to their face? That is called cowardice, plain and simple.
Talk about someone in the Anonymous subforum? You're a coward. Say it to their face. Men, in particular, should be ashamed when they do this because it means they lack basic masculine equipment, to put it politely.