My 2 cents:
1) There are exceptions, but I haven't found a sure way to tell if you are one of them.
Now that the original poster's question has been answered, let's elaborate agree and disagree on a few points made above.
The general rule of starting on a 250 - 500 cc bike is to my way of thinking directed at a "first bike". There are some folks here who say this is for your first "street bike" and dirt bikes don't count. I disagree, unless your dirt-bike experience is limited to a 70 cc dirt bike.
One reason often touted, and one I agree with is that it is easeir to learn skills when you don't have to contend with the extra weight and extra horsepower. I fully agree; why not make it easier to learn? Why would you want to slow the learning process by making it harder?
2nd main reason is you are highly likely to drop your bike while stopped, e.g. tip it over while moving it in the garage, forget to put the kickstand down, make tight turn onto main drag while looking at approaching traffic only to realize that you have to stop suddenly while leaned way over due to lane suddenly being closed in front of you (you should not have skipped your coffee that morning), some other stupid dumb reason. Here it pays dividends to have a old already scuffed up bike, or at least one that you haven't devalued by a couple of grand by putting a scratch on it.
Third reason is that a 600 and up will get you in trouble before you realize it. Well that is partially true. Things like throttle control while goving over a bump if your have your wrist in the wrong position on the grip can give you problems, and you will find your self approaching that corner at a buck twenty instead of 80 before you know it, but you can compensate, learn proper technique and get to know your bike slowly. HOWEVER, this only delays the problem; if you start on a bike that is very capable at speed, you will have your first crash two years down the road instead of in the first 6 months, and since it will be when you finally think you know what you are doing, after taking a couple of years and many thousand miles to get to know your bike, and you will have it at a much higher speed, because you still need to recalibrate your internal speedometer - a painfull process (trust me on this).
I know folks have good intentions when they say that a smaller modern bike with about 50 HP bike outperforms older b***** bikes. This has not been my experience. Most 50 HP and under bikes seem enemic, once you have ridden a SS or even an antique but modified 750. My learner cycle was also an old 750, but with a few mods (cams and cam timing matched to header lenght on HRC 4-1 exaust for maximum peak power, Lektron carbs carefully tuned to match, modified intake-forget exactly, heads ported/polished, a little boring, pistons,....etc). It made a 750 Interceptor seem like a pussy cat.
As to reasons to want a b***** more powerful bike, no it's none of the four reasons quoted by Jim Moore above ( 1. It's pretty. 2. I don't know any better. 3. All my idiot friends have one. 4. I'll pull MAD trim on this thing, yo. There can't be any other reasons). The only true reason is that you are addicted to adrenaline and power. That's perfectly understandable. Let's just admit it, and decide how you will deal with your addiction. Like an alcoholic, you can have a two-drink limit or go cold turkey, or exercize restraint most of the time - a very dangerous way to handle it, but the most fun way.
Given that we are admitting our faults, let's deal with the speed thing. Even if you have years of experience on big dirt bikes, and you are not so worried about the speed of the learning curve or handling torque and traction, you know nothing about road riding at High Speed. Do yourself a favour and get a 500 as your first street bike.