You're right, it's not valid to make any broader conclusions from an anecdote. But it's about just as valid as the author making conclusions based solely on physical "this is what I should expect to happen" hypotheses.

More importantly, as an individual, the only thing that counts is when the n of 1 is you. As another commenter said, you don't need to live your life by studies. It's not like there is much expense or risk in trying a screen reddener, so try it out, and if it works for you, great - it's bizarre that the author thinks it is "aggravating" that a lot of people use things that they say work for them.