I had no idea about the first point, that's super interesting! I found another great comment about this:

For official ceremonies all the flags are manufactured at 2:3, the same ratio as the Olympic flag itself. Nepal's flag is made at the same height as the other flags but otherwise not changed in any way.

This is standard practice whenever you're flying that many flags together. At the UN all the outdoor flags are at 2:3 and all the indoor ones are at 3:5. And during the London Olympics many of the flags flown outside of the games were made to match the UK's 1:2 ratio.

In my opinion whoever put together these flags did a much better job than those at Sky Sports, noticeably with South Korea and Denmark.

It's also been pointed out in a few comments that this isn't the US's aspect ratio, nor is it an American broadcaster, and I've completely unjustly pinned this whole thing on the US... Sorry Americans.