And the 2nd part also needs a citation especially the villify part. While I am aware of the studies that you are referencing, they usually focus on sexual attraction. But relationships are not only based on sexual attraction.
https://www.theatlantic.com/science/archive/2018/08/online-d... - see the chart by age
https://metro.co.uk/2019/02/22/men-regardless-age-will-alway...
There are dozens of articles and several studies that confirm strong ageism in men preferences for relations. Few mention that single career women over 35 are the most unhappy people and a quarter are on antidepressants. From here to taking action against the relations of their age group men with younger women is a tiny logical step.
No idea what are the "certain circles around the web", but the overused word "toxic" gives me an idea: it it men in general? I saw the Gillette commercial.
Long time I hadn't that much of a laugh browsing HN.
The difference in maturity means it's harder to relate. I personally wouldn't want a young girlfriend, despite finding them sexually attractive, because I could not imagine trying to share my life with them - our interests would be too divergent. I think there's a real risk, when one party in a relationship is much less mature, the other party may have an unbalanced or unhealthy set of interests - interests that may end up hurting or harming the less mature party.
Doing that with a woman his age is almost impossible, fertility and children health when the mother is over 30 is declining rapidly.
In any case, that made me think about life a bit different. In the same situation I would do the same.
Societal pressure to vilify relations between older men and young women comes mostly from women. Studies (please google it) show that man of all ages 18 to 60 are looking for women 18 to 24. It has a perfectly clear biologic explanation: health and fertility, key factors for healthy children and the viability of the species. But that puts women, especially over 30, at a huge disadvantage if they don't have already children and husbands, so they punish the young women in these relations for obvious reasons.