Unless you're party to an elite camp's setup, how, as a fan, can you possibly know the intricacies and nuances of a football match?
To that end, what he's saying has to be right, but general tactics, foresight and formation decisions, non pros can get an extremely strong grasp on, and this can be proven by calling events before they happen on the field, which often happens on forums.
Also, don't people like Andre Villas Boas prove that with the right opportunities an outsider can become something in professional football management?
Are forum posters a representative sample of football fans though? How many football fans go on a forum regularly to discuss the game at a somewhat deep level? Very few, I'd say, of the millions and millions of people who would consider themselves to be "football fans" in England, the UK, or Spain (where I'm from).
In particular in Spain, and I've been noticing this for years now, the average football fan/supporter/viewer understands the game only at a rather superficial level: they basically celebrate goals, insult oppo players and fans and the referees, and yell very primitive and embarrassingly simple or wrong tactical notions. And that is the vast majority of fans I find myself surrounded by, be it friends, acquaintances or strangers. Don't get me wrong, I'm not claiming I'm better than them, because I'm certainly not, but I think it's obvious, at least from what I see, that outside specific circles like football forums, the game knowledge is extremely poor among fans, which is probably fair enough if the are enjoying themselves that way, but that doesn't mean that there's nothing more to it than goals, controversial referee decisions and Barça-Madrid rivalry.
That's not to say I agree with Kolarov or how he worded the idea, he very possibly doesn't know much more or understands the game any better than those fans he's talking down to. Neither am I claiming that pundits and in general ex-player are much better than many fans, which is awful in Spain as well, cringeworthy sport commentary is our daily bread too.