Put simply, an ideology is a belief.
One can make an argument for it, but it is still a belief. It is outside the scope of science. There will always be dispute about it. If an idea is scientific, then it is testable, and with time, almost everybody will agree with it. Galileo concluded that the earth revolved around the sun, and during his time, a lot of people were not very thrilled with that idea. But with time, more and more evidence supported the conclusion, Today no reasonable person would disagree with it.
The words communism, socialism, and capitalism, describe ideologies. The ideologies in the world today are very large in number with a lot of variations. Some people are very attached to their ideologies to the point where they think that if everyone accepted them, it would solve their problems. That kind of thinking is flawed. Ideological thinkers cannot be objective and often distort the truth.