They're half right.
Loving yourself is needed to be able to maintain high, or moderate self esteem. But loving yourself can't be set at 'obese' since that would be unhealthy and could have life damaging effects. BUT, to try and change someones opinion like that could, and might hate or dislike their opinions and/or self. So really you should just strive to love your physical and mental self with as little leniency to your weight as you can handle.
But you're right that saying 'obese is good' is a wrong statement, mainly for children/teens who will never try to change for the better