Yessir, it is indeed a competitive game. The intention is to win. People on the losing side generally feel bad about losing. On these points, we can agree.
However, your understanding that any action you take to further facilitate your success is "okay" is what I find warped. If you say there's no difference between beating your opponent in lane and having someone assist you in actively frustrating your opponent as your only goal, then I'd have to say your interpretation of social interactions are undoubtedly skewed.
Because there -is- a difference in someone being put out that they're losing and someone being frustrated that two people are actively intending to make sure that person doesn't have fun by constantly putting them at a disadvantage.
By your logic of "the ends justify the means", then I'm sure you'd think that drophacking and scripting should be fine, correct? They aren't just to let you know. Riot has voiced their stance on those activities in the past, and they consistently voice their stance on other activities in the Summoner's Code.