Bear in mind before reading into this post that, yes, some characters are easier to learn than others. Much easier at times, in fact. That's just how fighting games tend to go, really (at least, that's how smash goes).
If we all use our magnificent brains and think back to the discusion of character archetypes ( those archetypes being brain, body and heart) we can go on and easily conclude that being 'braindead' means requiring little to no tech skill. Personally I don't mind being the guy who uses the 'braindead' character as long as I like the playstyle or the character itself (Luigi fitting both of these requirements). What I don't understand is how people ignorantly call out how I, or some other player, only won because my character requires no technical skill. That's blatantly disregarding A) the two other types of characters (Heart and Body, which are equally as competitive as Brain) and player skill. Just because a character is braindead doesn't mean it's heartdead or bodydead (sorry for making these terms, but it's for the best). That being said, there were characters that WERE dead in all these areas to the point where it was unhealthy for our metagame (Luigi and Diddy come to mind). But, my point is, just because a character is braindead doesn't mean the character is incredibly easy to use at top level play.
Take Cpt Falcon and post-nerfed Luigi. They fit the braindead category, but are very strong in the heart and body department. With those two, you have to read for your kills, or complete a combo to put the enemy in a unfavorable position (like a position where you can edgeguard). But they can struggle against top level play because top tier characters/players can exploit their weaknesses. Weaknesses that can't be nullified by technical depth because they simply don't have any. Just one more point, and this is tying it to melee Kirby. Kirby in melee is known for being ****e. We know this, but do we also know just how easy Kirby is to use? Seriously, his game consists of suicide tactics and getting the foe offstage to use his surprisingly decent air game for edgeguards. Kirby is quite possibly the most braindead character in Melee. Yet, guess what? He's still literal garbage. Being braindead doesn't mean free wins, it usually means your character requires work in another area of his/her game. Obviously it goes deeper than this, but just getting the basics out.
I'm not trying to single out anyone who rants about braindead characters being essentially free condition, as much as spreading a bit of knowledge as to why some characters shouldn't take much technical skill. Anyways, I'm tired and it's quite possible that this post is either gibberish or just a bunch of bad points sloppily thrown together. So I'd like to end it like this: I'm sure most of us know by now that being 'braindead' isn't necessarily a bad thing for a character, but those of you who don't; understand that should see that every original character has certain strengths. Some of those strengths require technical skill, others require other skill sets. Don't use 'braindead' as an excuse as to why a player outplayed you. And finally, to those who take offense to the term 'braindead': why do you listen to those ignorant people who complain about your character. You know that your character does and what there strengths are. Don't listen to others as to why you won, because their rationalization is what we call 'Johns'.