Maybe they didn't search... big deal. Maybe they missed the search link, or maybe they were just too tired or frustrated to think to search first.
Maybe they saw that topic, but assumed discussion had wandered off-topic, as most long discussions do in pretty much any unmoderated forum, and figured they would be more likely to get help in a new topic. Perhaps they were hoping a solution had been found, and they could get the final version rather than read through pages of complaints and suggestions that may or may not help.
I know you much prefer everything neat and tidy, but if someone has a critical problem with a game they just bought (whether it is a game bug or a problem with their system) and comes to the forum for help, being abrupt doesn't make the best first impression.
