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So, it makes sense that if someone is just going through the suggested edits queue, they may not be the most familiar with the specific technology or the details of the questions and may make a mistake as to whether to approve/reject something. Requiring two votes makes sense in that context.
But in the context of a particular post, when you click on
edit (0) (for example) below that question, it seems the approve/reject should be immediate and only require one person. If you're clicking on that edit link from within the question page, you're probably familiar with the technology (or you wouldn't be looking at the question far enough to see an edit), and you've already read and understand the question. So you are likely to be in a position to evaluate the edit more accurately than if it was just some random question you encountered in the suggested edits queue.
The specific use case I encountered was a badly formatted post, with non-formatted code blocks. I was going to edit it to add code blocks, but someone else without edit privs beat me to it, adding a suggested edit. I went to approve it, but it still required approval of one more person to take effect. In the mean time, the post was still sitting there badly formatted.