This truly is the case, however one also needs to take into consideration range, the movement speed of the character and the opponent's positioning (location on the stage, state of movement, move lag, etc.). If the move has more range on it, then its immediately less punishable due to the opponent not being able to be in position to punish with a move (see Kirby vs. Marth). If the character moves like say Fox, the range gets extended due to how fast they can get into position. Also, moves on characters like Ike would tend to not work against most opponents, but with clever abuse of positioning (mind games) they can still hit. If they don't hit they still have relatively little "after lag" to take advantage of, and there is also the range to hurt the opponent's positioning. Naturally things like this can be difficult to discuss, but the likely-hood of reaching some kind of agreement afterward is much more likely than saying...
"DK gets ***** by Kirby because Kirby can gimp him! 60-40 Kirby favor!!!"
(I know you don't think this, I'm just giving an example
Also, no worries. I love heated discussion if the other person knows what they are talking about, and you certainly do.