It is not about what I think. Its what the bible says about it.
Deuteronomy 18:10 There must not be found among you anyone who makes his son or daughter pass through fire, a diviner, a soothsayer, an enchanter, a sorcerer, 11 a spell-caster, a consulter of ghosts or spirits, or a necromancer. 12 For whoever does these things is detestable to YAHWEH, and because of these abominations YAHWEH your God is driving them out ahead of you. 13 You must be wholehearted with YAHWEH your God.
By what you are saying you can (for example) watch porn and not be in sin, because you dont engage in it.
But watching /listening or reading bad things will influance a person, and in time will make you drift away...
If you're not comfortable with reading a particular author then don't. It won't do you any harm not to read CS Lewis books. But I don't honestly see how you could be snared into sorcery or anything of the kind from one of his novels or essays, he didn't promote such things.