It could have been a fraud since I don't remember who funded it, but two or three years ago there was a story going around the news that someone had done a study claiming to find that vegetarians were more agressive than other people. Your Mr. Oswald made the memory of it return.

If it's even true it probably just means that a person willing to take a "agressive" stand on one issue is more likely to be "agressive" in other ways.