It's a complex issue and the mob wants a blanket ruling.
When I was 32 I was an ***** and a good match for my 20 year old girlfriend; I treated her with decency and met her parents, etc etc.
At 48 I wouldn't date a woman in her 20s because no matter how accomplished or smart she is, there's an experiential and emotional/intellectual gap that usually results in some disproportionate imbalances, and of course reality sinks in wherein you have to question (cynically) what each party in the relationship is after due to those imbalanced power dynamics. Yet I would argue it's not impossible.
The Twitter Mob et al (whoever they are) need to accept that a 20-year old woman has free agency with her mind and body, along with all the risks associated with that. The flip side of the coin is that a 40-something adult has a responsibility to recognize if they're in a position of power over someone and not abuse it. I would argue that Florence Pugh for example, has a significant amount of power and knows exactly what she's doing, age notwithstanding. Add to this a changing world where people live longer and marriage/kids is not everyone's goal nor is it forever.
You can join the military at 18 and be sent to maim and kill other human beings, but you can't have a drink and if you have *** everyone freaks out.
A strange culture we live in, Twitter or no.