This behavior as described by the researcher does not get XP for the player. It does not get drops for the player, either. It simply wastes the opponent's time.
Note also that there are two different behaviors described. One, a pattern of teleporting foes into the 'safe zone guards' was later defined as griefing by the developers, and punishable by pretty much the same punishment as threatening people. The other is a matter of waiting till someone is badly hurt, fighting someone else, and picking them off by teleporting them directly into a boss. This is completely legal, it simply imposes an XP penalty on the person killed. It is also, of course, viewed as 'cheap.'
I suspect strongly that our friend did the 'teleport into guard' trick until the day it was declared griefing, then switched to a new tactic, just to cause the maximum social annoyance.
I have seen this behavior in real life, as well. It is the person who drives in the left lane at ten under the limit, on a road where the convention is twenty over. Much like the behavior described in the game, it is technically legal, unless, of course, the cops decide the driver is intentionally blocking the road.
In this case, I suspect he is both intentionally blocking the road _and_ driving with a hat on, barely able to see over the windshield, if he truly does not understand why his behavior was deemed frustrating.
To put it another way, most of us grew out of this behavior when we were six. It's passive-aggressive, and spiritually the same as "I'm not touching you. I'm not touching you. I'm not touching you."
His survival _after_ this behavior might be an indication of skill... but I doubt he survived for long, simply taking advantage of the lack of death penalty, and various stealth powers to return to play after being killed.
As far as playing by the 'rules', I should note that it has become harder and harder to perform his tactics, due to behavior like this. Why? Because, while the game world may allow it, it was only allowed because the developers didn't actually believe someone would behave like this, to no personal gain and great social cost. As such, they have added equipment, power sets, potions, and direct power changes to make it harder to perform.