I can't speak for everyone, but you are probably being downvoted for two reasons:
1) Apologia does not meet "I'm sorry". Read the first few sentences of the article for an explanation.
2) I shudder to think of a world where everyone felt the only criteria for whether it was all right to do something was legality. We should all be grateful that most people don't go through life with that mindset.
I knew what he meant by apology - it was an explanation on why HFT is not unethical. However, I felt writing such an essay showed the author is insecure and has doubts about his profession.
It's an intellectual, not ethical, defense, as he explains in the second paragraph. His defense has nothing to do with remorse and everything to do with helping people understand the concepts so they can participate in an informed debate.
1) Apologia does not meet "I'm sorry". Read the first few sentences of the article for an explanation.
2) I shudder to think of a world where everyone felt the only criteria for whether it was all right to do something was legality. We should all be grateful that most people don't go through life with that mindset.