Demonic deception, among other things, keeps people all wrapped up in the problem so they do not focus on the solution. It keeps people all wrapped up in doctrinal discussions unrelated to our daily walk and keeping the commandments, the things we should be doing to serve God and our neighbor. As the departed Jacob Marley said to Ebenezer Scrooge, "Mankind was my business. Their common welfare was my business." (paraphrased if not exact)
See posts #119 and #120 on the Genesis Chapter 3 Continued (Fourth Try) thread.
That is the sense in which demonic deception is worse than you realize. Religiosity, even Bible-oriented religiosity, means nothing at all.