Clearly understood it better than you guys.
The ending is interesting because it completes Joel's transformation into the villain. The quest is really Ellie's, Joel is just getting her there. If it were a film, Ellie would have been considered the protagonist. But gameplay requires action, so they have you control Joel to protect Ellie. There's a reason added on the front on the box, and why the DLC is about her.
For you guys, villains apparently have to be blatant and obvious. David is a villain to you guys because he's a cannibal.
But what Joel does is arguably worse. After all they have been through, Joel decides to rob Ellie of her agency, much like everyone you consider to be a villain in the game. What makes Joel different? That you controlled him at some point? Who cares?
If nothing else, the railroaded ending proves that they wanted Joel to go full villain at the end.
By the end, Joel doesn't view Ellie as her own person that can make their own choices, or as an adult. He doesn't respect her at all. Instead, he violently and selfishly takes away her choice, then lies to her face about it. And she knows it. She's stuck with yet another person who won't let her make her own choices. She's stuck with a man who will murder innocent people to ensure she doesn't get that choice.
So what game were you guys playing?