So is the message behind UBW that superhero/capeshit ideals are retarded and anyone who unironically believes them needs to grow up?

UBW was a bad ending. You can't convince me it's not. It makes it seem like it's good. Shirou doesn't find his own ideals, still hanging on to the same childhood dream that isn't his. I don't even think he learns the truth about Kiritsugu in this route. And everything about the ending is leading back to the same tragedy Archer went through. It makes everything he went through pointless.