I used to bring up gluttony alot. From my experience, most people, including myself, bring this up as a means to justify other vices. It's obviously a very valid point, and I completely agree with all the reasoning as to why gluttony is bad. I've just found that by bringing it up, it's usually because you're ashamed of another vice that people keep haggling you about. What you do about it is your own business, but I'm saying that once you realize that those people who are pointing fingers are gluttons, you will have this hate in your heart that cannot easily go away. I've destroyed some friendships because of that hate, which is obviously not good. Just keep this in mind. Basically, no, there is no excuse for gluttons, they are no better than a pothead or drinker, even though they will try to say otherwise, but pointing it out and having a hateful heart doesn't help them or yourself.