If Hurley doesn't go w/ Locke, Jack & Sawyer wouldn't have had to go back to rescue him, and may have been able to start the island evacuation earlier, possible staying ahead of the freighter explosion. I dunno, I'm just pitching here. That line does seem very odd now.
That wasn't the quote. I forget what it was exactly, but something along the lines of going w/ his emotions caused something Sayid regretted. Nothing about not killing someone on the island.