Here's why:
* It modifies a verb, adjective, or another adverb. For example:
* "They are ideologically opposed to the plan." (modifying the verb "opposed")
* "She has a ideologically driven agenda." (modifying the adjective "driven")
* "He argued ideologically against the proposal." (modifying the adverb "against")
* It describes how something is done or to what extent something is done.
Let me know if you'd like to see more examples!