If you look at policies, people overwhelmingly support policies, initiatives, laws, etc. that progressive groups champion.
If you look at how people rate themselves and people they know, they will simultaneously say that they are all moderates or conservatives.
Politicians further misunderstand the overall lean of their constituents, because the loudest and most consistent voices are regressives screaming that all conservatives are with them.
Add to this that progressive groups tend to be focusing on actually doing the things, while regressives can quickly build a fantasy world and just all agree to repeat it ad nauseum, and you've got a perfect storm for people to not have any good way to actually describe the world they want to live in.