I don't think it's a choice. I think a lot of bad habits are developed throughout childhood very often and then it can take a lot of time and effort to correct it.
I've tried many times to lose weight, many different ways. Yeah, it's as simple as eating less and moving more but if you've been significantly overweight and struggled with BED or compulsive overeating then you know there's more to it than that.
One person might excel where others fail. I personally can't eat things 'in moderation'. I'm learning I have intolerances and that I fare better eating certain things.
People are plowed every day with information about 'how to lose' and then when it doesn't work were are we to turn? To the next thing, hoping it will help. Sometimes this can take years while you try to find the right path. That obese person, unless you're watching them eat a supersize McDonald's meal in front of you, might be on their 48th attempt. Just trying to find what works best for them and can help them.
So I don't think it should be considered a 'choice', because oftentimes once someone's decided to take the step to lose there's a myriad of things to sift through and mistakes a plenty to be made before the weight can come off and stay off. This could mean years of obesity spent just trying to figure out how to get the weight to start coming off.