If you'd really lost a significant amount of weight before, you'd know that exercise does not lead to weight loss. You wouldn't suggest it as a solution to anything.

Exercise is an important adjunct to weight loss. Just for the purposes of feeling good, you need your body's emergency response to the loss of caloric reserves to not include cutting muscle to lower your basal metabolic rate. The only way to do that is consistent exercise. It is critical to healthy loss of significant amounts of weight. But it isn't the cause.

So if you wanted to show off how superior you are to everyone with lives that require them to spend time on stuff other than losing weight, if you knew what you were talking about you'd say something like "imagine taking drugs instead of eating less." In addition to being cruel and mocking, your comment indicated a clear lack of understanding how the body even works.