I know many people claim that the Civil War qualifies as such , which may very well be the case , however I'm looking for other examples since the very subject of whether it qualifies or not seems to be greatly debated by many ...
Also while I'm aware that the Whiskey and Green Corn Rebellions qualify as being directed at the federal government/being " grassroots " in terms of being rebellions originating from the discontent of average people in a bottom up way as opposed to being fomented by elite actors , however ( AFAIK ) neither of them resulted in many casualties and the Green Corn Rebellion was put down by a local posse as opposed to federal agents and/or American soldiers ...
Anyways I hope that my question makes enough sense and thanks ahead of time for any answers !
Could you be more specific than "alleged by many?"
Hard to imagine anything that even comes close. Sympathy for the Whiskey Rebellion was much more widespread than western Pennsylvania. It was symptomatic of a number of issues that the populations of the western frontier had with the eastern-controlled state governments, and so there were many on the entire frontier who sympathized with it. But no, there were not thousands of casualties, nor were there in any other popular uprising other than the Civil War. Even the Battle of Blair Mountain in 1921, which involved more than a thousand striking miners, had likely less than 100 casualties; and the only reason you could call it "rebellion against the Federal government" was the prosecutor enthusiastically decided to charge the miners in custody with treason.