Even though my weight has been around normal for quite some time, I have had weight issues for most of my life, and I've got to say it's not easy to lose weight without having a concentrated effort to do so. That means that if you rely on a certain schedule in order to maintain a livelihood, for example, taking that extra step IS so hard, because you have to change your whole life drastically, and sacrifice a lot of other things.
However, that being said, if you're fat and you really aren't doing much of anything, that's entirely your fault. Having the right weight just makes you feel so much better.
On plane seats, I agree with the OP. I hate it when the media glorifies plus-size people. You're fat, there's no reason to be proud of it, you should be embarassed that you're taking up the space of others.