I am indeed no medical expert, but in my opinion that is just a bunch of bs. How much and how hard you feel you baby move, again in my opinion, depends on the baby's size, position, and on your own size.
I finally started truly feeling my baby move about 19 weeks. I say truly, because before then I really couldn't determine the difference between baby movements, gas, and muscle cramps/stretches. However, since feeling that first movement they have only increased in frequency and in intensity. Sometimes it feels so strong that it seems she could be punching or kicking straight through my stomach.
I am at about 25 weeks 3 days now. Normally I feel my baby move a little bit every 2 - 3 hours. Some days I barely feel her move at all. The times that I feel her the most, and the strongest, is when I am laying down. So far her most active and strongest punches and kicks come sometime between 8 pm and 2 am. As of my ultrasound on december 16th my little one weighed 1 lb 3 oz. I am pretty sure she weighs more now, because my middle is growing bigger by the day.
I hope this helps to ease your mind a bit.