The post-count requirement is a way for Sequential to require a degree of commitment to the forum, based on a member's involvement in it. It's difficult to gauge this by the date when a member has joined, since perhaps most members only read, rather than participate in, the discussions. That may not appeal to you, but I'm just offering an explanation. There's more junk that passes through this forum than you might expect, and it somehow has to be sifted.
If it's any help to you, very few people advertise their used instruments on this forum, and presently there are no Pro 2's for sale in the Marketplace.