Not sure what you are trying to get at with the phrase "Off the shelf ideology". The fact that other people have thought about this before? If so, I'm not clear why you would think this would be bad - the alternative is convincing yourself that unless you've come up with the idea fully formed yourself, it can't possibly have merit.

I would agree that anyone who blindly follows what someone else has written in a book without bothering to consider whether you really understand it, whether it actually makes sense, and whether it needs to be modified to suit your particular circumstances is clearly not much of a thinker.

But taking and developing ideas originated elsewhere doesn't seem an intrinsically bad thing to be doing.