They sound like they never grew up.

You pretty much hit the nail on the head right there. A good majority of Millennials weren't raised with proper parenting techniques and are basically arrested development cases. Their parents wanted to be their kid's friend instead of being a role model and disciplinarian. The kids were coddled by their helicopter parents, and the parents made it so they didn't have to face any sort of adversity or failure. Sports or other group events? Nobody keeps score, everyone gets a participation ribbon. Kid got a bad score on a test at school? Parent goes to the principal and bitches about the teacher's techniques. The kids didn't have to deal with feelings of loss or failure, or to have to learn about fair play and personal achievement. Nobody drove them to excel or improve based on their merits, and I believe that this contributed to their abhorrence of a merit-based society. They were given head-pats and cookies for just existing, so why shouldn't society do the same for them now?

Though what "free thinking" do they have when they all follow the same cult and are in to censoring and banning free speech and art now a days?

Yeah, "free thinking" has always pretty much lent itself to being counter-culture, and back in the '60s and '70s that typically that meant standing up to authoritarian rule - which, to be honest, was pretty bad back then. The problem now is that the "free thinkers" of today have become the exact thing they rallied against 50-odd years ago. They, themselves, have turned into authoritarian types that are trying to impose their will upon the populace, with tactics involving racism (disguised as "diversity"), fascism (disguised as anti-fascism), and attempts to push their control over the way people think and speak through both coercion and force. It's like they read Orwell's 1984 and took it as an instruction manual instead of a cautionary tale.