I disagree with this idea. Humans are only a small percent of the Federation's population, yes, true. However, humans seem to be the only ones, or one of the few species, that have gone out in-mass to explore / exploit and colonize the galaxy. In my view, humans make up the lion's share of Starfleet personnel. In Kirk's time, at least 50% if not 75%-80%. In Picard's time, they are still at least one-third if not half of Starfleet.
I don't think knowing the percentage of humans in Starfleet is "crucial to understanding and appreciating ST." I was speaking more of incredibly basic things even hardcore fans seem not to understand.