I checked the account and it appears to be sincere lol
That is absolutely a thing, influence agencies pose as part of a group to manipulate people, to make the whole group look bad, as agent provocateurs to justify actions against that group, and whatever else.
Anybody involved in the non-establishment choice for Democratic nominations should be well aware all social media is overrun with fake people pushing an agenda.
I am 100% sure many of the conservative aligned ones did so pushing Harris at her anointation because they knew they could beat her. The Establishment has their own obviously.