OH, how fun it was to be naive.
In melee, to counter one character, you played another. This is called counter picking. Just because you have found that one character is good against another, does not mean that you have somehow stumbled upon a new revelation. In melee, jigglypuff counter space animals, the spacies countered shiek, shiek countered marth, marth countered peach (examples merely), and so on. Every character has good and bad matchups, the bad characters are the ones who have no or very few good matchups. For instance, Coreygames is not good because he has no idea about yoshi's matchups, or anything involving yoshi for that matter, and should stick to characters he knows something about. I edited for you, but i agree with most of what you said
.