As a kid, I always found men wearing an earring cool. I also remember that I never really noticed which particular ear was pierced - left or right - but I did notice when both the ears were pierced.
Then around high school, I learned of the “left is right and right is wrong” rule.
One of our classmates was an Indian-American (India - as in the South Asian country!) - and someone had visited his house to discover that his dad had both his ears pierced - though he was not wearing any earrings or studs (would have been one cool dad if he did that - I think!). Between snickers, I heard a couple of my friends spouting that rule.
(This Indian friend later told me that his dad hailed from the Indian state of Rajasthan, where there is a tradition to pierce both ears - for men and women - when they are very young.)
The rule of “left is right and right is wrong” basically went like this - if a man had his right ear pierced, it meant that he was a gay, and if he had his left (only) ear pierced, meant he was straight.
This never explained both ears pierced - if it meant the guy is a bi, I never heard that explanation.
Fortunately, this rule - as ridiculous as it is - is long dead and gone. I almost never hear any young kid talking about this. Its a good thing that no one bats an eyelid when they see guys with both ears pierced.
For guys - it does not matter if you get your left ear pierced or the right one - or both. As long as you are able to carry off the look, that is!