What happened is basically a 650 twin or 600 single makes half the power of a 600 four (and with a more friendly torque curve), so they are offered up as a compromise- 'It's not as tame as a EX250, but at least it's not a ZX6R'.
As a bonus, they are honestly very solid balanced bikes you could ride your whole riding career. The EX250's have notable shortcomings if you will only own one bike, for many years. I certainly advise starting on a smaller bike and upgrading, but many people obstinately refuse that course. I'm not sure if they are afraid of losing money in the process, or if it's an ego thing.
As a bonus, they are honestly very solid balanced bikes you could ride your whole riding career. The EX250's have notable shortcomings if you will only own one bike, for many years. I certainly advise starting on a smaller bike and upgrading, but many people obstinately refuse that course. I'm not sure if they are afraid of losing money in the process, or if it's an ego thing.