This "Sora shouldn't be in Smash because Disney" argument really doesn't work because it either relies too heavily on slippery slope arguments or takes a weird moral stance against his inclusion.
"But you can't represent him without Disney so that means we're gonna get non-video game content"
Kingdom Hearts has more than enough original content to work with to where they don't even need to touch the Disney stuff. The world of Kingdom Hearts is so vast that Sakurai can represent the series perfectly without referencing any of the movie worlds. And before anyone says anything about Donald and Goofy needing to be in Sora's Final Smash, reminder that Cloud doesn't have Tifa or Barret in his either. Not every JRPG character has to have a team-based final smash. Yeah, it'd be neat to have them there and it'd be one of the few scenarios where I'd be okay with Sakurai breaking the "no non-video game characters" rule, but they aren't necessary to Sora's moveset.
"Disney's not a video game company so Nintendo shouldn't negotiate with them"
Neither is Microsoft and we have Banjo in Smash. Company of origin doesn't matter as long as the character is from a video game.
"But Disney is evil and I don't want them touching my Smash"
We currently have three Konami characters and Disney is where you choose to draw the line? Don't get me wrong, I absolutely despise the company's business practices, but it's not like we don't already have shady companies working with Nintendo. Again, Konami has treated its employees like **** for years and majorly screwed over some of its biggest creators, yet I don't see anyone complaining about Snake or the Belmonts being included. It's fine to not like Disney, but don't act like Sora's inclusion is going to somehow ruin the game's moral integrity. Disney and Nintendo have already worked together with Marvel Ultimate Alliance 3, so I don't see how Sora in Smash is any worse.
I totally understand if people don't want Sora in Smash, Kingdom Hearts isn't everyone's cup of tea. However, don't try to make up slippery slope arguments to justify why your opinion is objectively correct when those same arguments has been disproved multiple times.