<p>Some searching on <a href="http://meta.stackoverflow.com">http://meta.stackoverflow.com</a> came up with the following:</p>

<ul>
<li><p>According to <a href="http://meta.stackexchange.com/questions/87890/why-cant-i-suggest-edits-on-se-meta-sites/97371#97371">http://meta.stackexchange.com/questions/87890/why-cant-i-suggest-edits-on-se-meta-sites/97371#97371</a> it's due to the fact that it would add an another burden to moderators which is explained by the following:</p>

<blockquote>
  <p>Mostly because the per-site metas are generally low traffic -- some of
  them count daily visits in the <em>dozens</em>. </p>
  
  <p>That means the moderators will have to do the work, since the 10k site
  users are the only ones that can even see this queue. And on many
  sites, like say Bicycles -- there are exactly zero users at this rep
  level, even after many months.</p>
  
  <p>[...]</p>
  
  <p>We were uncomfortable adding Yet Another Queue for Moderators to Look
  At across every site in the network.</p>
</blockquote></li>
<li><p>According <a href="http://meta.stackexchange.com/questions/78223/per-site-metas-dont-have-ability-of-suggested-edits/78319#78319">http://meta.stackexchange.com/questions/78223/per-site-metas-dont-have-ability-of-suggested-edits/78319#78319</a> (which is older than the above answer) it's a feature that is not needed on meta sites.</p></li>
</ul>