To be fair, Kenny Rogers came in for a lot of stick when his eye surgery came out looking wierd and awful, and Barry Manilow doesn't escape the critics, but yes, women do come in for more of it.

Ironically though, as you say about Madonna -

"And that’s just because Madonna has committed the cardinal sin of ageing in the public eye and tried to conceal it for as long as she could." - it's sad that she's trying to coneal it because doesn't that make her much like everyone else who won't let women age in the public eye?