How are people with 120+ lag on top of scoreboards?

Darn can edit... Just wanted to say, I know there are a lot of complains about high lag players. This is not what I'm asking though, I'm genuinely trying to get how that makes the game any easier, considering my own relatively laggy experience. 

120-170 ms lag is still playable if you don't have other options. I had an Iranian guy in my clan back in the day, he had stable ~120 ping and he was always at the top. It feels pretty bad, but if it's stable, you just need to adjust your reflexes to that. Moreover, if you have high ping, it's a bit harder for the enemies to kill you. So yeah, it's quite realistic to have high score with high ping.

Because people with lower pings get lag added to compensate and you do worse. It lags out the whole server. If I'm in a game with no-one above 100ms ping, everything is fine. 

Once you learn how to abuse lag, you can be a unkillable monster.

If you're still trying to play like a normal human, you'll suffer.

But how can you abuse lag? People keep saying that, but I really don't get how that works. The only meaningful thing I can see online is players being more difficult to track, but I don't think I've seen this when playing against them (certainly apart from a very, very few cases, I've not seen player models stutter or teleport). 

Time Nudge and Server Rewind, the server is the referee and determines who wins the gunfights, skill has little to do with it sadly.

You gotta be good to abuse the lag, it favors aggressive playstyle meaning you have to have experience and be aware of the lag while you play and adjust your plsystyle to it 

At 65ms you should be an annoying player to shoot at and have a gun fight with. You need to land your initial shots because the enemy is shooting at your after image hit boxes

We dont want to create another monster

It's because people with high ping see you first before they appear on your screen. Around 150ms ping is the sweet spot for the lag abusers, since the time to kill is so low on this game they can kill you before you even have time to fire black. 

Something similar happens with console players. Since the PlayStation/XBOX networks are so slow, console's get a similar advantage with the de-sync. 

Why I want PC only servers with gamepads banned to bring back the real BF experience. But sadly looks like BF franchise has gone all in on console cheese so I have to move on.  

Ok that’s what I don’t get: if they are the ones lagging, shouldn’t they see you last rather than first? Say you both are about to turn a corner and meet: it takes say 150ms for the server to update them about your position, but only 20ms for you to have the info. 

I genuinely don’t get how it favours the laggy player.