I do personally think they're on the same level of problematic unless one side is actively engaging with the creators about it.

For instance, people sending problematic fics to creators or the people in Niki's chat truthing ships, for instance.

To me, fiction, opinions, and thoughts are all the same level of problematic because they don't actually affect anything. (Unless you slandering someone or engaging with creators about it. For instance, you can believe X if you want to, but I don't think you should go around genuinely saying "this person is X")

I will say, the line between shipping and truthing is a lot blurrier than people act. Especially these days.