Fans:

Realizes the writer/artist own the characters and IP.

Let the writer/artist decide how the story goes.

Discuss plot points and acknowledges plot holes

Debates what’ll happen next season.

Adheres to established lore/previously released material

Porn.

Fandoms:

Porn

Tells everyone their “ships” and belligerently defends them.

“Head Canon”

Complains, loudly, that the “non-hetero coded” character being hetero is bad.

Defends “cousin Oliver” characters.

Thinks the writer/artist don’t own the IP, the ‘fans’ do.