There is no question that Alexandria Ocasio-Cortez has excited the base of the Democratic party, especially the younger generation. She, along with Bernie Sanders and others, are working hard to expand the base of voters by attracting the many people who have been disillusioned with the party and with politics in general because their interests and needs were ignored.
This of course is upsetting to the party establishment that seeks to maintain their control because these new voters are less likely to go along with the tired old policies. The party establishment, as represented by people like Joe Biden, still cling to the myth that they can attract back white working class voters who have defected to Donald Trump. Biden keeps talking about building bridges with the Republican party (he even talks of possibly having a Republican vice president!) despite the fact that they treat him with utter scorn.
These people hate AOC because she threatens the establishment but she is also very popular with her constituents. So what to do? They think they see an importunity because it is predicted that after the next census, the state of New York will lose one congressional seat. This means that the boundaries will have to be drawn. So party leaders are salivating at the prospect of redrawing her seat so that she will be running in a district that is less favorable to her.
AOC is a savvy politicians and knows this and is already taking steps to counter this move. But it is very revealing that a priority of party leaders is to seek to get rid of a person who has so excited the party base. It shows their true colors.