To me on the left or right for that matter is just making you aware of something or someone. I prefer the track shout when it’s a rider though, ‘Stay’ which is definitely not ‘Get out of my Way’ 
3 Likes
When I was doing tris, being a crap swimmer and a FOP cyclist, I learned very quickly to either not say anything or “stay right” when I was passing others. “On your left” almost invariably led to riders moving to their left. 
2 Likes
Sounds like bullshit to me