They're probably still going by their logic that he can't be in because of Waddle Dees in Smash Run.
Even if Bandana Dee hadn't fought Waddle Dees before, a no-brainer: they can just make Waddle Dees not spawn during that round when Bandana Dee is being used.
I take it you haven't seen their thoughts on him in the past?
They think it's a huge stretch to add him, he has a 0% chance, and that Captain N, Nester, and a Pilotwings character have much better chances than him.
Hey Andre and Derrick, you know what else is a stretch?
Judging a character's chances when it's fairly obvious you know barely anything about them.
Especially when there's these kinds of threads:
GameFAKS deserves it
The conclusion: We should be thankful Sakurai is actually educated on the characters he considers, unlike these lot of people. Especially when he worked on the Kirby series at one point (even though he didn't give Bandana Dee the role he has now), and the retweet in the OP.
Even if Bandana Dee doesn't get in (Even though I'm quite positive he will), I'm sure Sakurai will have known about his importance and give him a better role than AT, unlike some of these people..