It is a harmful stereotype to label obese people as lacking willpower as you have done. Many obese people don’t have the resources (time, money) or tools (nutrition understanding) to improve their situation. Many have metabolic or familial history of obesity which has both physical and psychological (normalization) impact on their ability to control their weight. The former can be helped with diet and/or medication, the latter often causes them not to seek help.
Most people in the US live in poverty and make marginal spending food decisions based on money per dopamine reward unit rather than optimizing nutrition. McDonalds is cheap and unhealthy; fresh fruits and vegetables and the free time to educate oneself on proper nutrition, then cook healthy meals and do meal prep often cost more money and time than most can afford. As does proper exercise when you’re working 12 hours per day trying to make ends meet.
A less harmful way to phrase your point is that medication can help people who self-medicate with food overcome metabolic efficiency. I lost 40 pounds on semaglutide (Wegovy) so far this past year and dropping; exercise and diet alone didn’t work for me. I hope to eventually not rely on medication to maintain a healthy weight.