I disagree.  I see what you are saying, but facts are not ideological (if they are taught plainly).  For example, "ice is cold" is simply a fact.  Teaching of facts does have some ideological underpinnings (demonstrable truth), but in the sense that ideology enters this discussion, that is not relevant.  We can teach facts, and we can teach ideology about what those facts mean.

Fact: some people are homosexual.  Ideology does not change that, but it does put various spins out how one reacts and interprets that fact.