well, because other internet forums are run by tools and full of tools, and they can all eat our dicks.
whatthefuchsia.com was originally created as a bit of an extension of the old bbs days. nearly ten years later, and most of the people surfing around nowadays have never heard of a bbs, much less actually used one. the idea of a linear message board is foreign to people, and actually seems to elicit a horrifying response.
so, for your benefit, or your lack of benefit as we generally disagree that threaded forums actually help start conversation, we added a way for you to view it like other forums. head over to your board preferences, and select 'threaded' in your 'view style'. hit 'save', and you'll see your forums in a somewhat familiar way.
warning: if you've used your favorites pretty heavily and switch to this new mode, your favorites are going to change slightly. every thread you visit, the last message on that page will be your new saved spot in the favorites. it will never drop, but you could miss out on other messages if you aren't keeping track. also note that any board you visit that isn't in your favorites will be added to your favorites as you browse messages. you can delete them at any time by visiting your favorites page.