The Min is quite high. AS cards can pill for pill against him. Power Manips with a lower min than him can pill for pill against him and even beat him. I.E Dreadlash. Cards with Power Manip + Attack Manip like Sue, Nellie + Herman even Prince Jr.
The power does have quite a high min, although it is a very solid card. And it is sort of predictable but that can be used against you to ways.
As for me, the only answer is that people were busy voting ban other cards and forget him for one or two weeks. UR staff couldn't give him a perma-ban, since they banned Askai (I don't know why I sold him as well as my Jungo deck when he is not Elo banned) and Troompah, so they leave him for players.
In my opinion, he is the most solid nuker in Elo at that time. You can show some cards those can be used to counter him, but I don't think you cannot name a better nuker compared with Ongh at the moment. Kerozinn Cr and XU52 are some cards those are in the same level with Ongh, however, as you can see, XU52 is banned quite regularly and Kerozinn Cr now is banned more often as FPC becomes more popular.
"the min is quite high" he has the Power of 8 and can gain 2 life
Straight from the start he has a three pill advantage and if you dont win 3/4 rounds or just beat it you will lose