Democrats are not a monolith; it's a diverse party. It sounds to me like the people who responded to you with nastiness were moderates, or "establishment" and your POV is further left, e.g. democratic socialist.

That said, in the last few months before I quit Twitter, I made a couple of tweets in gainsay to some left-wing talking points, and I was absolutely swamped by the tribe trying to whip me back into shape. Anything I said remotely challenging to the left wing echo chamber branded me a Trump supporter and troll.

So my takeaway from what happened to you is twofold: one, moderates are typically harder to convince about bothsidesism, and two, no matter your position, social media exacerbates tribalism.

Sorry for the hurt your encounter may have caused you.