The goal of wresting the Democratic Party from the clutches of its corporate masters and turning into a true party of peace and justice is a noble one. The goal of returning it to the days of FDR, LBJ, or even JFK is a misguided one.
From what I've read, Alexandria Ocasio-Cortez is sincere in her socialist leanings. She has some knowledge of the implications of advancing a socialist policy agenda, and why people (voters or not) will embrace socialism if they feel that capitalism has failed them. Does she know everything about it? No, but then who really does? I also perceive that her message gets muddled by the people who feel that they have a right to use or co-opt her voice.