Dave the Gnome you may not be commenting on the ads themselves but you are commenting on those who object to them. You are misapplying their objection to another medium in an attempt to ridicule it.

Use the word bitch if you want to in a song but don't expect every person who hears it to like it.

Both ads are offensive in their own way and I wouldn't put them up in any public place. I'm not sure whether bitch or bastard is more offensive. We'd either have to compare "All men are bastards" to "All women are bitches" or, "Ditch the bitch" to "Dump the bastard" to find out.