Operating outside of ideology is extremely hard, if not impossible. Even groups that see themselves as non-ideological, still seem to end up operating within an ideology of some sort.

Take for example Less Wrong. It seems to operate within a few assumptions:

1.  That studying rationality will provide use with a greater understanding of the world. 
2. That studying rationality will improve you as a person.
3. That science is one of our most important tools for understanding the world.

...

These assumptions are also subject to some criticisms. Here's one criticism for each of the previous points:

1. But will it or are we dealing with problems that are simply beyond our ability to understand (see epistemic learned helplessness)? Do we really understand how minds work well enough to know whether a mind uploaded would still be "you"?
2. But religious people are happier.
3. Hume's critique of induction

I could continue discussing assumptions and possible criticisms, but that would be a distraction from the core point, which is that there are advantages to having a concrete ideology that is aware of it's own limitations, as opposed to an implicit ideology that is beyond all criticism.

Self-conscious ideologies also have other advantages:

• Quick and easy to write since you don't have to deal with all of the special cases.
• Easy to share and explain. Imagine trying to explain to someone, "Rationality gives us a better understanding of the world, except when it does not". Okay, I'm exaggerating, epistemic humility typically isn't explained that badly, but it certainly complicates sharing.
• Easier for people to adopt the ideology as a lens through which to examine the world, without needing to assume that it is literally true.