One of the quirks of human psychology is something called "source confusion." This is where we remember some fact, but forget where that fact came from. This applies to moral lessons as well as general knowledge. It's the reason why we read bedtime stories to children about talking animals who engage in good moral behaviour. They probably won't remember the details of the story, but, if exposed to enough of these stories, they will integrate the morals of these stories into their belief system.
This happens with adults as well as with children. It's why religious texts are full of parables about good men doing good things and bad men getting what is coming to them. It's why authoritarian regimes have sought control over the media and banned books and movies that are against the morals of the state. Because people pick up on the morals of the fiction they consume, even if they understand that it is not representative of reality.
The average young person in the West has consumed more fiction and mass media than just about anyone in human history. And the average tumblr user has consumed even more than that. If you constantly consume fiction, especially if you don't supplement it with non-fiction (history, science, philosophy etc.) or real world interactions with other humans you begin to develop something I call "fiction brain".
I think this explains, among other things, the way that tumblr went from being the feminist man hating website to the soft uwu MRA website. Your conscious mind may understand that your blorbo is not real, and he is not representative of the way a typical man is. And may in fact be nothing more than a fictionalised representation of what a woman wishes a man was. But in your subconscious mind, the boundary between your blorbo and real flesh and blood men begins to blur.
This may manifest itself as an inability to interact with actual men, and form human connections with them. As they do not think and act the way you have subconsciously conditioned yourself to believe they think and act. But an even more harmful effect of this is that you begin to perceive rhetorical attacks on real men as attacks on your blorbo. Even if the rational part of your mind knows that Castiel is fictional, you still grow defensive when men are criticised because the irrational side of your mind has formed an emotional connection with him. So when you see feminists saying mean things about real men you feel pain, because you feel like they are attacking your blorbo.