that they aren’t necesarily skilled nor even licensed riders. You like the look of bike “a” and that’s what they’ll sell you. You like bike “b” and that’s the one for you in their eyes. Not all the time, but much of the time. Selling a supersport to a new or even an average novice rider is irresponsible IMO.
Having said ALL of that…the 650 is a lot of bike, but should be fine for you for a long time. As I say here often on similar posts: I’ve owned plenty of bikes including sport bikes, sport tourers..you name it. The most fun bike in my garage to ride every day is my wife’s M620 Ducati. I’m a big boy too at 6’4, 240…and 43 year old basketball knees. Bikes in that class have the right weight, HP and Torque to be a lot of fun without being too peaky. They are much easier to enjoy on the street. My R6 track bike has an engine builder red-line of ~16K. Power curve is between ~11K-up. It would be a PIA to ride on the street.
HTH…