I suspect that many young people who are open to socialism are more likely to equate it with the generous welfare policies of Canada and various European nations than Venezuela or Cuba. Bernie Sanders himself has pointed to Denmark as an example of the kind of nation he thinks we ought to try and mimic.
As for Ocasio-Cortez, she indeed does have a lot of growing to do as a politician. But to be fair, everyone has to start somewhere, and I think it’s easier to defend voting for an inexperienced representative than, say, an inexperienced governor (like Arnold or Jesse Ventura).
I do find Tom Perez’s comments to be quite odd, though. Americans on the whole have not warmed up to the concept of socialism, so it’s surprising to me that he’d enthusiastically embrace someone who calls herself a democratic socialist, especially with the midterms right around the corner. It’s a risky move on his part, IMHO.