And you can't read, "bruh".
It's rational because that's the limit of the obligation. When you're married, you've an obligation to the family unit. When you divorce, your only obligation is to the children, if there are any. Divorce is, and should be, the severance of
all ties, legal and otherwise, to your spouse. That's the entire point.
Right back to the appeal to emotion, which is irrational (as are all arguments of emotion). That divorce might be "unfair" to one spouse is not a valid argument for the other to be indebted to them. Even a purely objective perspective that one of them "sacrificed" their career, etc, doesn't justify the other having to make "support" payments to them. That's what the division of assets is supposed to cover.
And making that argument doesn't even justify it from a legal perspective because most of the states that do allow for alimony do so under the premise that the spouse has the "right" to maintain the same standard of living they had while married, which is even
more insane. And in many cases, there's not even any children. So again, no. There's no rational reason for alimony to still be a thing. Though I can see the appeal to your every day white knight and gold digger.