You see, the situation could have been avoided several different ways.
1. Read a different book in public.
2. Use illusionary methods to disguise your book.
3. Conversation redirection.
The first one is as easy as it gets, you can read plenty of good books in public that usually wont cause a stir. The books in the recommended Satanic Reading list come to mind.
The second one is something I came up by myself which works too
well, and it's very simple. I've been reading Sass' Essays in Satanism
in public, using one of my illusionary methods, and no one is the wiser.
And finally in the last one, if you choose to be reading Satanic Literature in public, Lesser Magic plays a pivotal role in this method. It would be better to have avoided the situation altogether in the first place, but there are some ways you can fix the situation.
If you don't want attention in that manner, don't give people like that something to latch onto. The masses cannot effectively understand, and you know what happens when large groups of people don't understand things-- The inquisition and Crusades come to mind.