The Lets Run crowd are immature youngsters and Slowtwitch is old guys trying to hang on.
I honestly probably had not too far off the mindset of those younger kids on ST, who assume that since they can run a 5k in 20 flat with basically no training, that anyone who can't do it is a total slacker and underachiever, and that anyone with the 'proper mindset' could run a 16 minute 5k if they just tried hard enough. (Not that I ever came close to 16:xx!) Ahh, the follies of youth.
Now that I'm older, wiser, and fatter, and have pretty much pushed near my limits on running (and less so swimming/biking), it's pretty clear that most of the assumptions I had as a 18 year old were flat out wrong, and that the fast guys have a lot of genetics to thank for their speed. Not that they don't bust tail when they have to, but they even have the genetics to allow them to bust tail AND go fast.
I'm faster now than I am at age 18 due to more focus on endurance sports, but it's def been a humbling process. And a good one!