That too is immoral and degrading.
I'm not a fan of such large age differences between couples, but unless the younger one is not of age, I don't call it immoral.
I once knew a billionaire who was closing in on 80, and his live-in, long-term girlfriend was a bit under 30. Do you consider it a little more moral if both individuals are over 25 or at least one of them is a rich dude?
Like I said, I don't condone such wide age ranges in couples, but I don't consider it immoral. Just short term and therefore useless. The exception would be the mormons, who used to commonly have much older men marry young teens (12-14). That that was frickin' immoral, because guys seldom, if ever, had the best interests of the child in mind.
I do have on question though. How long is your list if immoral things? Does it include hangups that aren't sexual, or are you careful to limit your condemnation of others to that one arena?
Or is everything immoral, including vanilla ice cream and running through the sprinkler on a hot day? That is, are we all such sinners that nothing we do can ever be anything but immoral and degrading?
And you just pick the juicy ones to complain about, right?