I heard this from many different riders. Pirates think you need a 1200cc+ V-twin and squids think 600cc I-4 is a beginner bike and you should get a liter bike once you learn to ride.
I think its ridiculous. I’m 6’2″ 220# and ride a Ninja 250R. I have had no problem accelerating away from traffic at a stop light or accelerating to avoid a merge on the freeway. The bike will do 90+mph. How much faster do you “need”?
Sure a 1000+cc bike will accelerate much quicker than the 250 and you probably won’t need to down shift twice for a quick acceleration but the little bike works just fine. But starting on a smaller bike makes learning much easier and less dangerous. How many youtube videos can you find about new riders getting on a big bike and having it take off into the side of a car when they screw up the throttle and clutch? A small bike gives you much more time to recover and produces much less panic at that point. The light weight allows you to learn to handle the bike without much fear of dropping it at the slightest mistake. Riding twisties on a light bike is easier and it give you the chance to really learn to ride.
Craig