I was a skinny kid.
Either my allergies or asthma medicine made lots of foods taste terrible, so I couldn't stand to eat them and eventually developed scurvy, a form of malnutrition caused by vitamin C deficiency.
Back then there were no clothes sizes for people who weighed more or less than the average, so I usually had to use safety pins to hold up my skirts and blue jeans.
And I got teased all the time by other kids for being skinny.
Even as a teenager and young adult I was thinner than most people, and got teased a lot, especially by overweight people. I never teased anyone about their weight, but they probably did get criticized and made fun of for being fat by others.
Finally, in my early 40s, I got up to what the medical charts say I should weigh.
But I always notice when I see or hear other people getting criticized or teased about their weight and it's far more likely that adults will make comments about others who are underweight than overweight. We all know it's rude to call people fat, but it's equally rude to say someone is skinny.
Yes, being extremely under or over weight can cause health problems (and is often caused by health problems) but people with those conditions are aware of them and don't need to be reminded.
Please, everyone, grow up and quit what amounts to verbal bullying.