I don't think fleitz was being sarcastic per se - certainly I didn't read it as suggesting human evolution was a 'bad thing'. Rather pointing out that (at the

I don't think fleitz was being sarcastic per se - certainly I didn't read it as suggesting human evolution was a 'bad thing'. Rather pointing out that (at the time) oxygen in the atmosphere was hostile to more complex forms of life. As we know, oxygen is a pretty unpleasant element in its raw state - but we managed to work around that particular problem.