Cthulhu, it isn't you having internalized a bunch of concepts important to the game. Well, it is, but the point is that shouldn't prevent new players from doing the same on some level. Before I started playing I spent a few days reading articles and studying professional matches, and quickly learned more once I started playing. Granted, I'm still a newbie, but it isn't slow going. Basic concepts like "don't run out alone when the enemy team has map control", "don't get into fights that don't favor you", seeing ganks in advance based on your positioning and enemy presence/absence, etc. aren't the sort of things that take four years in university to learn. Hell, you can be in your very first match and still understand things like that if you have a lick of common sense. If you haven't picked that stuff up by the time you hit level 5ish on your first account, there's something wrong.
I mean, you won't see high-level tactics and planning from low-level randoms, but the people who constantly feed and get themselves into bad situations are either doing it intentionally, or are really that stupid. I ran into a guy the other night who insisted that playing Ashe solo mid was an awesome idea, then decided to go jungle after we all shouted him down around the time of his third death. After he died to jungle mobs a few times he went AFK because he "AM Fukin sick of u nubs telling me what to do i should be able to play who i want where i want, im a experence player and know what im doing".
Heh, a good chunk of the reason why I started playing Teemo is because it lets me ward for the whole team without spending all of my gold on wards, because goodness knows nobody else buys them. Well, not quite. Maybe ~10% of my matches have been with people who worked together and grasped basic concepts, and perhaps half of those had people who kept wards up. It's not that they don't exist, just that it's rare to encounter them. In a sense it's actually quite similar to SCII random multiplayer, in terms of the mix of players you get.