Why does the "cougar" stereotype of older women who date younger men persist so strongly when almost none of it is true?

Why does the cougar stereotype of older women who date younger men persist so strongly when almost none of it is true?
As a woman engaged to a significantly younger man (I'm 42, he's 26) I get super annoyed whenever someone calls me a 'cougar'. The term 'cougar' implies a lot of stereotypes I've found to be mostly (or almost entirely) false (both from my experience and the experience of other women who are with younger men)

1. The older woman does the initial pursuing (Flat out false. The vast majority of the time the younger man does the initial pursuing. I was actually fairly hesitant at first because of the age gap)
2. The relationship is mostly sexual and neither party is interested in commitment (Mostly false. While there are a few exceptions to this most older women and younger men in a relationship are very interested in trying to work it out long term. Yes, there is a sexual relationship, but there's a lot more to it then just that)
3. The older woman is having a mid life crisis and trying to regain her youth (Mostly false. With only one exception, every woman with a younger man (including myself) was in a very good place in her life she was happy with prior to the relationship starting. There is some truth in this in that younger men often bring an energy and fun that the older woman is attracted to, but that doesn't mean she's having a mid life crisis and trying to "regain her youth")
4. She's probably paying him to be with her (Super false. There isn't a single older woman with a younger man I've talked to who is paying him to be with her. In fact I've offered to give my fiancé money when he was in a tight financial spot multiple times while we were dating but he turned it down every time I offered.)

Why do so many people believe these stereotypes when the overwhelming majority of older women with younger men don't fit them? Where are these assumptions coming from? Why are they so prevalent in our society?
Why does the "cougar" stereotype of older women who date younger men persist so strongly when almost none of it is true?
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