I would like to point out to you, Yyore, that the "Only" in OnlyPenetration, is actually not part of the name of the skill.
Every skill of every class has "[Class name] Only" written at the top right-hand corner, and for some reason, some skills have the name of the skill right up next to the "Only". Punisher has two active skills, and one passive skill like that: Penetration, Plasma Bomb and Intermediate Health Mastery.
Punisher isn't the only class with the "Only" right next to the name of the skill. All of them have at least 1 like that (Intermediate Health Mastery).