The point is that the MAGA movement is already extremely violent. Their threats are being carried out. The issue is bigger than idle “threats”. The actions of these domestic terrorists have already warped life in America.
This isn't a contest of what's worse. The point of the article is that the threats are making it so that people who are critical to stopping Trumpism afraid to the their jobs, meaning they in a lot of cases they don't do their jobs. The acts of violence aren't going to kill enough people to cripple the left, but the threats might actually terrorize enough people into standing idly by while the fascists take over.
Don't use one problem as an excuse to write off a related problem because it's "worse".