I have no issue with someone being objective and acknowleding that they lost/lose games because they play a bad character. Why deny it when it's true? Unless you are playing Fox (or maybe other characters depending on match ups) you should feel as if your character has design flaws that are ultimately hurting your game.
I have some scrubby friends and they can beat my Pichu. They beat me cuz I played Pichu, I can 4 stock them with probably 7 or so characters so I am obviously the better player. Think of it that way.
Mango went Falcon vs Westballz @ AMT, Mango lost the set. He literally lost because he went Falcon. There is no doubt in my mind that he would not have lost if he went Fox. He didn't exactly take that game too seriously but he still lost to someone who he is better than because he played a "bad" character.
of course we all like to play to our own constraints/rules for fun/hype/self-challenge/etc. and by all means we should, or the game would become kind of stale. but at the end of the day, if one player makes the decisions he should be making to win within the constraints of the game, and the 2nd player says 'i could be doing <insert description>, but i dont want to, but if i did id be the best,' very few could say that the 2nd player is better if he loses to the 1st player
the 2nd player is cooler though
Lack of evidence does not imply lack of existence, player two could certainly be better but of course that is not inherently obvious nor is it implied.
Next tournament you go to whether or not you make it into bracket or you do it in pools go Mewtwo and you'll probably lose to someone you know you can beat with your main and you'll probably say, "wow I can beat this scrub, *insert name here* but mewtwo is so bad, he sucks, and is holding me back."
And you'll say that phrase exactly

. This might sound pointed but it's not. I just think it's true and something everyone should understand. I feel like you know this (but don't really want to stand by it) though when I look at your word choice but yeah.
tl;dr
At the end of the day no one wants to hear anyone john about their character, including myself, but it definitely makes sense for the better to lose because they are playing a bad character and there is nothing wrong with the better playing acknowledging it, because it's true. Get what I'm saying?