Bringing this to a human level...Wouldn't you consider a deception to be dangerous? Say...... Satan has an idea to deceive the children of God. Would you not consider that to be dangerous? Isn't false doctrine an idea.......leading God's children astray?
An idea is presented to us. We analyze it, and get a good/bad value. We then reject the idea, or accept it, and then take action - sometimes delayed - based on that analysis.
E. g., I have an idea to bop my brother in the nose
Analysis: Sounds good - he stole my candy 20 years ago.
Delay: Wait until he's in reach
You'll notice my analysis may be faulty. Also, my brother is safe from my idea until I execute it. Also, I may reconsider my analysis, and reject it the second time around.
Finally, I would put "belief" in the execution class: I analyze an idea, accept it as valid, and believe it.
As to false doctrine, I can understand the idea without accepting it as true.
Them's me thoughts, and I'm stickin' to 'em until I don't!