Well, more the population has grown every day, it is seen there is more consumption of meat and is also wasted (including meat around the world). The theory is false and made by one type minded people. A unwanted habits of consuming alcohol is another added factor to this issue. About violence, it is to do with freedom of speech, the more man runs his brain freely with his thoughts sharing/imposing on others causing increase of differences in opinion. Powerful people make use of this fact and run the world on their thoughts and the weaker/sub-minder will suffer causing decades of unsolved continuous violence where millions of deaths are witnessed every decade.