The problem is the word socialism gets thrown around s lot, and is more often than not used incorrectly. When people point to successful "socialist" countries, they are almost never socialist. They are capitalist with high taxes and extensive social programs, not true socialism .
Some of the Democrats that espouse "socialism" really only are advocating high taxes and extensive social programs, some actually do want socialism (which is scary). But this conversation never progresses because too many people refuse to use accurate terms.