It's not that you're zooming in, it's that you're taking a screenshots from a YouTube video and using a single part of that one screenshot to judge the entire game.
Compare the picture I showed to the one you're showing and look at how much more detail all the textures have... now imagine if instead of looking at snapshots of a video you were playing the game on your TV with no quality loss from video capture(let alone taking snapshots of said video) and it will look way better.
http://abload.de/img/vlcsnap-2015-10-12-20dcr7r.png
[IMG]http://abload.de/img/vlcsnap-2015-10-12-20xiptm.png
[IMG]http://abload.de/img/vlcsnap-2015-10-12-20vgqqe.png
[IMG]http://abload.de/img/vlcsnap-2015-10-12-209zq2k.png[/QUOTE]
All of those screenshots prove his point.
Your screenshot only looks better because he's closer to the textures that are blurry in the first image. If you look at the textures that are that distance in your second screenshot you will notice that they're blurry as well.
Just look at the third gate on the third screenshot, you can see that at that distance the ground textures become extremely blurry because Halo 5's texture filtering isn't that great.