Scope of idealism & materialism?

[weusours]

I get the gist of materialism (material world shapes ideas) and idealism (the opposite). But I'm not sure how far those terms extend.

Suppose Person X agrees with Group A on Issue 1 but strongly disagrees with them on other issues. Issue 1 is the most important issue to Person X, and Group A is the most important group working on it. Yet Person X refuses to work with Group A because it would violate their ideals (or principles, or whatever, the word is not the problem).

To me that sounds essentially idealist. Person X is letting their internal picture of how the world is (or ought to be) get in the way of getting shit done in the real world. An essentially materialist person would go the other way.

Or wouldn't they? Am I using the terms too loosely?

[Point Blank]

IMO that would be better defined as an uncompromising/sectarian approach versus a pragmatic/opportunist one.

Person X is "idealist", maybe, but not in the philosophical meaning of the term.

[weusours]

I guess to me it seems like the practical person is essentially materialist because they set principles aside and adapt to material reality. The doctrinaire person seems essentially idealist when they stubbornly cling to their principles even in the face of unbending reality.