There is no "argument."
And this isn't a discussion of the whole menu at Sci Fi diner. The question was, what do people think of the new picnic burger at Sci Fi. This discussion did evolve. But my own opinion was rather simple -- it sounds disgusting beyond a few bites. It is hard to imagine any person with reasonable eating habits even being able to finish off a whole plate.
As to.. It doesn't matter what you eat for 1 week on vacation per year -- that really is te equivalent of saying, I'll smoke a pack per day for a week, but quit the rest of the year. How's it any different? Smoking is no more unhealthy. But our cultural attitudes treat cigarettes as poison nowadays. Meanwhile, our attitudes about unhealthy foods, is more like the attitude about smoking in the 60s. (I know it's not healthy... But I only smoke half a pack per day, and I only smoke filtered tips, so it's not really that bad)
I do 100% agree with you about focusing on quantity. Portion sizes is really the overwhelming problem. A fast food children's meal today, is the same size portion as an adult meal just 1-2 generations ago. The typical American restaurant plate, is usually a double - triple regular portion size.
Go to Paris, where restaurant eating is even more prevalent than America -- and they use plenty of butter, fat, carbs -- but the portions are half the size you find at typical restaurants here.