@Blondie
Yeah, good question. You're an intelligent woman and these questions must be asked.
If someone called my mother a bitch, I'd be upset.
Of course, context matters - let's say my mum is alive (she's not - she's been dead for 15 years) and someone calls her a bitch to her face. That's outlawed in UK law under disturbance of the peace. That's right, us UK citizens can't go up to some random schmoe in the street and yell 'bitch!' (or 'nigger', or 'slut' or 'white bastard' or 'Paki', or 'faggot', etc.) in their face. But, free speech means that calling someone names on social media or as a joke is kinda ok. It's not disturbance of the peace. If someone called my mother a bitch on FaceBook, well, that's covered because of free speech - I don't have to read those nasty posts about my mother. If I get offended, it's because I chose to read those nasty posts about my mother.