I edited this question by changing the title and it was rejected (I kept the body unchanged due to past experience with editing). I wanted to add a tag related to the phone but it didn't exist. It was later on edited and approved (I am fine with the edits made by Andrew T.).

When I started with editing posts, there used to be many of them rejected because I only changed capital letters or corrected a few grammatical errors or formatting that were not considered not good enough. I learned from them thanks to a moderator who told me what I can and should not do to make my edits better. Although I have carried on with editing posts, I refrain myself of others (usually when checking first post, I just click Skip even when I see there are possibilities to edit a post). But when a moderator or high reputations users modify the posts, even when their changes are not that different from what a user with a low reputation would have made, they are approved (sorry, I am too lazy to find many examples; I will only mention the link above as example).

There is a question in StackExchange that deal with whether "Thanks", "Thank you" and such, should be kept or removed (edited out) on questions. There were some users who said that they should be kept, yet it was removed from the original post. There are other edits on the aforementioned post that are also correcting capital letters, punctuation, etc; and yet it was approved (I have made other similar changes to post like the one described on the previous sentence and they were approved).

Why are they (the edits from moderators and high reputation users) consider better? How does the edits that would have been rejected when made by a new user or user with a low reputation be accepted when moderators and high reputation users?

Note: I am not sure if I should consider myself lower or higher reputation.

Fun fact: I learned today that Community is able to reject edit.