The average SAT scores are what USNA says they are. They show the middle 50%, so scores from the 75th percentile down to the 25th percentile. Why would you doubt them? They are the actual numbers, from the actual latest class to enter. They reflect 100% of the mids who are in that class.
When you say “from all the people that I hear from,” you’re experiencing what’s called sampling error. It’s a common fault of statistical analysis. You’re taking a subset — I’m guessing from posts you see here — but not a randomly chosen one of the population of interest. I’ve read quite a few times here that candidates who post on SAF tend to be above average. Anecdotally, that makes sense to me.
Meanwhile, USNA is giving you “perfect” information. In your words, “actual.” It’s far superior to your own sample of “a candidate here, a candidate there.”
