Do you need to log in every time you want to make a comment? In the past I didn't need to log in to make a post. I think a log in was only required once per year.
It might be something to do with your browser/anti-virus settings and if cookies are being cleared on exit from the site. I use several browsers and some used to require login but that hasn't happened recently.
"The rules are simple: They lie to us. We know they are lying. They know we know they are lying, but they keep lying to us and we keep pretending to believe them."