It's not ridiculous to think words would begin to get deleted, but it is ridiculous to say some government organization would sit there and watch him type to remove some content. Why would any organization spying on him make it so obvious, and pointless. If he wanted to hide it from them he would just go to another computer.
I run into this self'deleting in words once a month. I have no idea how I activate it, but when i type it deletes what's in front of it. It's a frustrating feature that I haven't defeated, but I don't think the government is watching my computer, seeing what I type on Hacker News.