"'not-too serious' incident, but Me Too appear to believe there can be no exceptions"

Precisely. Thus treating rape and a lewd comment as equivalent and equal offences."

If indeed Me Too believe that there can be no exceptions (I haven't studied their modus operandi), it doesn't follow that they treat every offence as equivalent and equal.

"Exactly what abuse are these women at risk of from an 81-year-old?"

I know a man who is eighty years old who is in the middle of a fifteen-year jail term for historical child abuse (dating back to the fifties and early sixties). He is absolutely no danger to anyone any more. But he ruined lives. Are you suggesting that he's, er, too old to be punished?