There are a few things to go on, but since I am not one of the two users that rejected your edit, I can not tell you what their thought process was.
The difference between é and e can be ambiguous to a native english speaker
The accents on letters emphasis the pronunciation, but they are still the same letter. In other words, "Pokemon" has **the exact same meaning* as "Pokémon". The only differance is that if you had never heard of it before, you might pronounce "Pokemon" with a silent e.
Users can not have an infinitive knowledge of the meta
You should not assume that just because it is on meta, everybody has seen it. Meta exists to argue our points, but sourcing meta when you make the change is a lot more efficient then assuming the users that will review it have read the same post.
The meta in question is ambiguous
The answer in no way states that this practice should be done. The only answer is a user reporting that they have made the suggested changes to their post, and only after deciding the rest of the title needed clarification. The title was "Is it possible to GIVE another player a Pokemon", so there was already question in regards to format.
Forcing the use of é is impractical
At the end of the day, you know what Pokemon is. I do not need to put the é in for you to be able to interpret exactly what I mean, it is just good practice, given it is the given name. That said, how many users do we have on here that know how to put the accent on their e? Short answer - you could not possibly know. Keyboards have an e character - but they do not have an é character. I would consider the forcing of é superficial just on this merit, alone.
In the end, many people consider only adding the accent to be insignificant, given the comments and feedback. Your edit should have been at-least been approved with the additional spelling correction, but personally, I would have hit "improve". It appears another user has made the correct edits to the question, with a more extensive edit to turn the question into something that makes a lot more sense. I reference you back to "are title edits superficial", where the answer effectively states "no, but make sure you go over the rest of the question, too"