The idea is that you can make it "your" front page of the internet with just the topics that interest you. If you go by the default it's got the most mass market appeal because of popularity but if you're someone who reads hackers news that is not what you want. So customize it.
The internet has become popular and just like pop music it will appeal to the lowest common denominator.
Reddit isn't required to make "your" front page. Personally... I just go into my browser settings and change it to whatever website I want.
More seriously, iGoogle is pretty good after being customized. I personally have email, calendar, and reader placed prominently (among others). I'd really like a hackernews synopsis too, perhaps something like hckrnews: http://hckrnews.com/
If you go by the default it's got the most mass market appeal
Well, not really "mass market" appeal, just appeal to the incredibly narrow and apparently homogeneous subslice of the world's population that fits into the reddit demographic.
If you're not aged 15-25, college-educated (or college-bound), left-wing, atheist, obsessively interested in every one of the typical geeky pursuits, and already intimately familiar with every one of several hundred reddit memes and running jokes, you're gonna have a bad time.
I'm not sure how many people there are among the world's seven billion people who fit into all those categories, but they all already have reddit accounts.
Also, I've noticed anecdotally that the average age on Reddit seems to have dropped over the past couple years. It used to be early 20s, but now I'm seeing tons of comments from high school kids and younger whenever I dare step out of the few subreddits I still bother to read.
I won't even get into Reddit's more serious developing issues like the explosion of casual racism.
...do you actually use reddit, or is this just something you believe?
As someone who only really fits one of your criteria (college education), I evidently don't exist, as I have a good experience on reddit. They have large communities for not-stereotypical-geekery like fitness[1], martial arts[2], and home brewing[3].
Yes, the uncustomized "homepage of the internet" is a giant wad of time-wasting activity. To be honest, that's what the internet is to many people, especially during their work day.
This is also IMHO why the whole 'karma' thing doesn't work. It's a measure of how much time you waste on the website, rather than any actual merit.
The people who waste the most time upvoting, commenting, etc, are the ones who decide the editorial. So you end up with a front page comprised of stories that people who like wasting their time online agree with.
The internet has become popular and just like pop music it will appeal to the lowest common denominator.