Well, if the principles of Liberalism have to be picked and chosen - "some more of this some less of that" - rather than all being objectives to be maximized, with very different policies and outcomes for a political governing body depending on they picked and chose to maximize and minimize, then that definition itself isn't sufficient to define a Political Ideology.
When you wheel out this definition and claim "this is Liberalism" in the context of politics you're not actually presenting a political ideology, rather you're presenting a bag of ingredients to make political ideologies with, quite a broad range of political ideologies even since some of the ingredients in that bag don't actually work well with each other.
It makes total sense in the context of discussing politics for other people to point out concrete implementations of Liberalism as being "Liberalism", since those things are the actual political ideologies cooked from the Liberalism bag of ingredients, though in all fairness it would be more correct for them to say "this is what's made with with Liberalism" rather than "this IS Liberalism".
Anyway, this circles us around to my original point that when talking about politics you can't just point out to the Wikipedia definition of Liberalism and claim that's the one true definition of Liberalism because what's there is not a political ideology but just a bag of ingredients which can be used in quite arbitrary ways - that's kind of like pointing out at a bag of fruit, sugar, eggs and flour and claiming it's the one true Cherry Cake to dismiss other people pointing at actual cakes.