I see them rag on capitalism all the time, but I'm not convinced. After all, the big, floruishing cities they often call home (LA, New York, Chicago, London) are very successful due to capitalism.
What they really want is capitalism (private ownership) combined with high regulation and high taxes to provide social welfare. I don't think they genuinely WANT socialism (workers owning the means of production), but they mistakenly believe that more welfare is socialist, which causes them to advocate for socialism.
This scares me. You can make an argument for more regulation, you can make an argument for more taxes, but workers owning production is such a stupid idea and they don't know how damaging it is.