It is by design. Meta sites don't allow users to suggest edits, even though there is a suggested edit queue; the only users who are allowed to edit every post are the ones that have that privilege on the main site, for whom the suggested edit queue is not used.
The reason for this is that, in the main sites, cleaning up posts is an important task, but it is secondary task on the meta sites, for which (hopefully) there are enough users with the necessary reputation to accomplish it. Considering the volume of questions on this meta site (319 questions on this site versus 12,002 on the main site), editing posts on this site can be done from the users with the right privilege.
The only meta site with suggestion queue is Meta Stack Overflow, but that is a special case, as Meta Stack Overflow is the meta site for Stack Overflow, but it is also the meta site for the full Stack Exchange network. There are plans to give to Stack Overflow its own meta site (where you cannot gain any reputation), and have a meta site for the full Stack Exchange network.