Example wasn't meant to be perfect, just saying Melee players don't value Brawl's merits over Melee's, and vice versa.I've never heard any competitive player say they aren't interested in new modes and extra characters, the implication that the competitive community don't/can't/won't also enjoy the game at a casual level for the content is somewhat insulting.
If the two don't come to the same opinion then it's because the casual player feels entitled to his style of play over all others or has a bad attitude towards competitive players, reasonable competitive players will want things that add to the games depth without scaring away casuals and if the casual player is arguing against them then it's just because it's something suggested by a competitive player.
I mean look at the change to the ledge that stops players camping on it due to a lack of invincibility, this is something that makes the game more interesting as a competitive game compared to brawl's ledge stalling, but this concept wasn't really something the competitive community was vocal about.
So now you have people calling it an "interesting change", but I can guarantee if the competitive community were asking for it before it was described there would be backlash too it, and if it was then implemented afterwards, people would complain that sakurai was pandering to a fanbase that doesn't "deserve" it or start being all "there, he gave you what you want now you'd have to be entitled to ask for it to be more competitive"
You have a point though: often times competitive players are the only ones upset about the changes, while casual players will enjoy the game however it turns out. Other times I've seen people say that they actively preferred Brawl's mechanics. We can't always group everyone into the same lines of thinking.
The entitlement issue you bring up, I think it's on more of an individual basis. There are people on both sides with bad attitudes about it.