Why can I edit a question on my own, but I cannot approve an edit on my own? For instance on cs.stackexchange.com/q/107194/68251 someone suggested an edit that I approved, but apparently needs someone else to approve it also. Even though I could just go and make the same exact edit myself. What's the logic behind this?

@ryan I don't know. You could ask on meta.stackexchange if you wanted. At one point Stack Overflow had problems with "robo-reviewers" who would approve everything in the review queue without paying much attention to it. It's possible this might be part of the quality control mechanism to deal with that

@D.W. Ah yeah I could see that being an issue. I might bring it up on meta if it hasn't already been asked.