I am aghast that anyone would actually take the side of 'there is no ageism'. Are they functioning in the same world I am? Or are they operating from a point of "proclamation" without basis.
I work in the creative industries, and I can say absolutely, without even so much as a glance toward doubt, that ageism is one of the biggest problems we have.
With only a tiny exception (usually accompanied by FU money) older creatives are shunned.
The only 'ism' that is not discussed to death is ageism. It may well be the most damaging of all since the other isms come along for the ride.