It absolutely can be. It was for me.

Is it for everyone? Perhaps not. But to outright unequivocally say it's not is simply outright incorrect.

It was absolutely motivation and discipline for me. One day I just decided enough was enough and I threw the proverbial kitchen sink at it.

I am perhaps an outlier in that I'm not ashamed to say I was obese in the past because I simply lacked the motivation and desire to do the work to change it. It was easier and more comfortable being fat than in shape.

I definitely agree telling an obese person to eat less and move more is about as useful as telling a depressed person to just stop being depressed. But lets not make outlandish claims either.