I teach drawing and my students are required to measure alignment of objects using their pencil as a straight edge whilst looking through one eye. Some students have trouble with this and have to place one hand over there non dominant eye.

Since I lost my left eye I have no trouble looking through only one eye. However, I have acquired plenty of troubles with balance.

I'm not a shooter, but people do the same thing when looking through a telescope, or a microscope with one eyepiece. You learn to ignore the other eye.

Considering the performance of the silver medalist, maybe thousands of hours of practice makes it moot, if you don't train yourself to require it.

Cargo cult, even at the olympic level, is a thing. See the mustaches that make you swim faster [1]. It wasn't only the Russian's that adopted it.

[1] https://swimswam.com/the-legend-of-the-mustache-in-swimming-...

He didn't reach the final in the men's event, so maybe they just had a good day.