There is a massive difference between Widow Twanky, or Hinge and Bracket, Dame Edna, and Les Dawson's female characters ... not really sexual beyond the lightest double-entendre, and we're not meant to believe they are anything other than men, that's the joke. They would have all used the men's loos even whilst in costume.
I am less happy with Kenny Everett's female characters - again we're not supposed believe they are real but the satire is much less pleasant and more sexual, more a men's view of women (a misogynists' view?) rather than a more general people's view.
Hinge and Bracket on the other hand satirize bickering and competitive elderly ladies - we can all recognize that this is generalization and also a version of something we've seen amongst some of our own elderly friends and relations. It is a more general view rather than a man's view.
I think a lot of parents let their kids see things at these shows that they would be uncomfortable taking their Grandma to. If it is not suitable for Gran it is not suitable for children. Years ago as a 16 year old I felt uncomfortable watching Kenny Everett with my Gran - that's how I know there's something not quite right. We need to trust our instincts.