"'Long live freedom and damn the ideologies.'"
-Poul Anderson, Past Times (New York, 1984), p. 141.
One meaning of "ideology" is a set of ideas that is generated by, then rationalizes, justifies and sanctifies, a status quo. Thus:
absolute monarchies generated the idea of the divine right of kings;
when James VI of Scotland became James I of England, thus uniting the kingdoms, he claimed to be restoring a lost Arthurian British unity, taking as his text Geoffrey of Monmouth's (unhistorical) History of the Kings of Britain;
the trans-Atlantic slave trade generated racism of skin color for the first time in history and with it came ideas of white superiority.
However, if by "ideologies," we mean simply theories of society, then we need them. In fact, we need several at this stage of history because we are in such disagreement. In politics as in science, theory guides practice but practice tests theory. We need not the practical instead of the theoretical but both of them and good theories instead of bad.