I already consider the Smash fan base as it appears online to be a vocal minority of Smash players because that’s just how it works for any game that sells 13+ million copies. Then within that community, very few people actually have some specific “anime swords person” bias that affects anything about how they conduct themselves. Much of that conglomerate tend to be more critical of specifically Fire Emblem and failing to vocalize that’s their issue and just go with the “anime swordsman” complaint wholesale. And even then, the anti anime swordsman people will often times come to the defense of the characters they like that use a sword like Isaac (Don’t give me that he could be more unique than others, the same can be said of Erdrick and a ton of other characters people resent for just being more of the same before they’ve been released and have actually shown anything off).
It comes off as a ****ty way to delegitimize the character choices that other people want and criticize a character they’ve never even seen. It’s not something that holds up to scrutiny when so few characters even fit that description and those that do, play quite differently from one another (Ironically the anime sword wielded Echo fighters are the most unique compared to their original base counterparts bar Ken who is just a semi-clone labeled as an Echo). There’s no aesthetic boundaries to Smash either and anime is entirely too broad of a term to use in criticism like that.
So, while I don’t have any data on that (and no one ever will), I have complete confidence in calling it a complaint leveled by a vocal minority of Smash fans. Especially when Sakurai has included 13 characters in Ultimate so far and a single Echo has included a sword in those 13 new characters... Like this hasn’t been an issue since Smash 4 at this point, and back then it wasn’t much of an issue since base Smash 4 only added 4 with Lucian, Shulk, Mii Sword-fighter, and only sort of Robin. Then Cloud and Corrin showed up via DLC with Corrin having stupidly specific circumstances to get included at all.