I too wondered about this when I first signed up - I did think to myself that even talking about contemplating suicide could be conceived as a threat & would therefore be inappropriate & unwelcome. I do fully understand the reasoning for the rule & sabby's clarifications make absolute sense to me.
I did wonder if the resources links under the depression forum & maybe a link back to the appropriate section of the main site's Resources pages, might be duplicated somewhere on the main forum index page - just so they're more immediately available for somebody in crisis? (My reasoning for that, is that when I visit the site, the main forum index is nearly always the 1st page I hit.)