I assume I'm below average

Naturally, the writer who is publishing this platitude believes that he is much more intelligent than anyone who might read it.

He is just telling them where they are in the heirarchy.

I definitely wasn't a good driver

Then you (if you are the author of this post) would almost certainly be incorrect or a liar. The majority of American adults read below a sixth grade level, yet you have published multiple books. You are likely aware of this, so I am going with liar.

I believe this lying is probably what you mean when you say in your other writing that you should adopt beliefs that benefit you rather than those that are true. I find this morally reprehensible.