My least favorite people in the Smash community has recently become people who love to complain about the Smash fans. These are people who love to lecture about how Smash fans only value 3rd parties over Nintendo characters simply because of hype (which to be fair does happen) while purposely choosing to ignore why it would be hype for some people. The kind of guy that would say the only reason people disliked Byleth was because they weren't a big hype 3rd party (hilarious when you remember that Persona only hit mainstream success a year before Joker was announced, DQ didn't have worldwide appeal despite being a monolith in Japan, Banjo hasn't had a game since the 360, and of course most smashers didn't even know what an SNK was). I call them Nintendo Knights, for how much they like to white knight the company. I won't name names, but I think we've all come across someone like this before.
What I dislike about them so much is that they prop themselves as these champions of "underdog" Nintendo characters. But if you actually asked them what 1st parties they would want to see, they will never mention actually wanting characters from new Nintendo IP. For example, they'll say they want a 9th FE character or PKMN over say an Advance Wars character (a series I'd like to remind everyone lost its Assist trophy, it's one real piece of representation, doesn't even have a song, and just got a remake making it relevant again) or newer Switch IPs like Astral Chain and Ring Fit.
At the end of the day they're just doing the exact same thing as the 3rd party fans, They just want characters from games they like. Which would be fine, but I can't stand the self righteousness of acting like you're championing underdogs while ignoring actual underdogs. While also still complaining about characters that they don't personally care for. I will never forget how so many people who unironically told you to let FE fans be happy for Byleth were among the first people to not let ARMS fans be happy over the announcement of an ARMS character coming to Smash.
TL:DR: They're just being this guy.