In 2018, I was one barraged by about 200 comments in the span of less than an hour in reply to my reply to a story on r/news about someone hitting a protestor with their car. For reference, I objected to violence against protestors.
The hundreds of replies were a variation of about three talking points: that people should be afraid of protestors, that the protestors will kill you, and that killing them first is justified. They were posting things like "What if the protestors drag you out of your car?", "If protestors bang on my windows trying to kill me I'm going to run them over" and or "If you stop your car, the protestors will kill you" etc. They also replied to other posts about the same topic on Reddit with the same talking points.
The posts used the same few phrases and the same punctuation and style. They would delete their comments if a comment's karma went negative and then reply to me again. Many of the accounts had similar naming patterns, and no other comments in their history, as well. r/news requires a certain amount of karma in order to comment, so they had to have deleted their old comments before replying in that subreddit.
I revisited the post and accounts a few days later and saw that some of the account owners had deleted their accounts entirely, and a majority of them had deleted (and not removed by a moderator) their violence-instigating replies to my comment, too. I figure some of them did this to keep the karma and recycle the accounts, and deleted the comments so they can be used in the future without it looking weird or getting banned.
I suspect it was coordinated in some way, even if it was just a bunch of people in a Discord chat.
But what stuck with me was that there is a somewhat large group of people who want (other) Americans to die. They want people to respond to free speech and dissent with murder. They want people to be afraid of what other people will do to them if they speak up and organize. They want people to fear each other so much that they can justify murder with that fear.