If I were on the jury, the donor would be responsible for child support for all of them.
There is no “jury.” This is all 100% legal. The mothers/custodial parents paid for the children and have supported them (perhaps with a few exceptions).
The one-line summary here is, “Adults with money get what they want.”
Meanwhile, a boy carries a copy of a sperm-donor profile to school, imagining he has a person for a father. And people who cry, “War on men!” over stupid commercials don’t care, because masturbation is funny.