You are absolutely right.
And never underestimate an enemy, no matter how strong or weak they are. It will get you killed.
You are 100% correct. Underestimating this movement is stupid. 40,000 people is a lot of people regardless of the size of the nation. Moreover, that number will only grow.
Having said that, I think this Democratic Socialist movement will do a lot more harm than good for the Democratic Party at first. We need to make sure the GOP (not GOPe) breaks their backs when they start to fracture the Democrat party. If they do that, the best case scenario for the Socialist Democrats will be controlling a few congressional districts in huge cities.
What the GOP can’t do is get complacent. Conservatives will have to be on their A game the next several election cycles to snuff these Demo-Socialists out and isolate their idiotic ideaology instead of letting it spread like cancer. The GOPe would paint these scumbags as “friends across the aisle” ... The Trump led GOP needs to paint them as the “Enemies of Liberty” and make their message the platform of the Democratic Party.
Finally, any major businesses stupid enough to support these dolts need to be called out instantly. There is absolutely zero call for an American company to be supporting socialists unless they want to be a sole provider of goods or service in a socialist economy.