That just shows you use "edgelord" as a meaningless buzzword instead of using an actual argument.
And dude, I've been a fan of Pokémon since I had the mental capability to be a fan of something lol. Incineroar is the best of the Alolan starters competitively by far thanks to Intimidate, which synergizes really well with its decent bulk and access to healing via Leech Life. Meanwhile Primarina's speed hampers it in its niche (though its typing definitely helps it) while Decidueye's stats are, admittedly, wonky, with many points wasted in Special Attack that could've gone elsewhere, with Spirit Shackle being the one thing keeping it out of total obscurity.
And that's coming from someone whose current second-most wanted Smash character is Decidueye.
HELL NO. There are so many things wrong there I'll have to split it in parts:
Primarina has a wallbreaking power that rips UU teams apart and can even cause some havoc in OU and BSS thanks to that monstruous SAttk and the great coverage he has available from his main STABs alone.
Decidueye is NU by usage since last month but still has great options on both UU, BSS and RU thanks to his Sinister Arrow Raid backed up by Swords Dance, and the potential threat of a suprise Curse set Mimikyu-style.
Incineroar instead has been stuck in NU since the very begginning and is essentially a worse version of Emboar, who is himself a worse version of Darmanitan.
Intimidate means nothing, there are a literal dozen of pokemon that also have it and unlike him, they pack the offensive and defensive stats and moves to back it up, the most prominent being, I hope you guessed it, Landorus and Gyarados.
Leech Life is a HORRIBLE option. Bug moves have bad coverage in general (ties for the most resisted type with Grass) and it does not even have STAB boost to justify using it. Just by saying that, I can tell you have actually no idea on how to play Pokémon, or at least, no idea how to play it against opponents that have some idea of what they are doing.
Look I don't really like Incineroar either but I don't think being competitively useless is a mark against any Pokémon in Smash. Pikachu is pretty terrible, Charizard is bad (mega evolution doesn't count because he doesn't have it anymore), I don't think Jigglypuff even has a single tier it's viable in since it's too strong for LC (I think), pretty much only Mewtwo and Lucario are good. And Mewtwo was powercrept by the Hoenn trio's new forms. And also Lucario isn't that good without Mega Evolution.
Consider that
Overused edgy looking design, on a pokemon that fares horribly on serious play? That is a recipe for disaster. For casuals it looks like an edgy Blaziken clone thus they don't like him.
For hardcore players, he is the second coming of Emboar: a useless pokemon completely outclassed at everything by older pokemon, that no one should seriously consider even in low tier teams.
And even in the anime he just appeared, he appears to be a Charizard replacement in personality and in battle, and no one is really too happy with that, not to mention everybody is getting sick of the anime after the sixth consecutive Diabolous ex Machina on the league, so he can't even pull some steam from the anime fanbase, either
And I forgot to mention, and thanks for reminding me; the seventh generation has been available for a while so he can't pull the "advertising placeholder character" like Lucario or Greninja did. He has nothing in his favor at all to justify a Smash inclusion.