If you look just above the forums search box, you'll see a small downward-pointing triangle of the type used to indicate a hidden menu.  Hover over this and select the 'My Settings' option, you should then be able to find the place to change the number of threads and posts on a page.

Whenever this question comes up on any forum, the answer is always "because it works."  The choices for most forums are to be totally unmoderated,  unmoderated posting but cleaned up by moderators after the fact, moderated or priveat/invitation only.  Private forums only work for supporting specific products, where the purchaser is a forum member.  Totally unmoderated get trashed and fail within a few days to a few months.  The other two are equal, except that the first requires more moderators reviewing content and the latter delays posts until the moderators approve them.

High traffic forums with fe moderators usually have to moderate posts.  Lower traffic with a higher number of volunteer moderators can moderate after the post.  But then you have to manage the volunteers.  Mercifully, in most forums at least, moderation occurs reasonably quickly.  Less so if you're several or many timezones remote from the majority of moderators.  The solution most of the time isn't to unmoderate the forums, but rather to moderate more often.

Or, become better known as a responsible member of the community and you get granted greater access earlier.  Earn the respect you're asking be granted by default.

Jeff