Why does it matter if it's late? I think if there's a game you're particularly excited for, you'd wanna play it near release, no?
And, as you mentioned, late ports usually sell less compared to multiplats available day-and-date. This can lead to publishers being less inclined to even do a late port if they think there won't be a big enough return on investment. Which is why people get antsy if their preferred platform isn't there at announcement.
It's one thing to wait for a game you know is coming eventually vs. a game that might never come at all. For example, I had no problems waiting for Dragon Quest XI on Switch cause SE announced at the very beginning that it would come to the platform, so there was nothing to worry about. But Persona 5 was a different story. Despite all the teasing (Joker in Smash, P5 Strikers, etc...), Atlus never gave any indication that they were planning to bring Persona 5 to Switch. That made the wait agonizing and a lot of people felt the need to constantly beg Atlus for the game to make sure they knew there was interest.
I think a lot of Nintendo fans are just tired of being treated as 2nd class citizens by 3rd parties. Sure, the Switch did a hell of a lot better than previous Nintendo platforms with 3rd party support, but it still wasn't ideal. Obviously given the power difference, we can't expect everything on the Switch. For example, publisher deals aside, I would understand why SE wouldn't port FFVII Remake to the Switch. But why can't Atlus give us Soul Hackers 2?
Regarding double standards for "late port" complaints, I think it's pretty simple to explain from a console wars standpoint. If the game in question was previously exclusive to a single platform, then it's seen as a victory to "steal" it and it doesn't matter if it took a long time. However it it's a game that was available for every platform except one at launch, then it's seen as "just a late port" since a lot of people on the other platforms have already played it. A lot of the time when Switch gets a late port, it falls into the latter category (though 13 Sentinels and Persona 5 specifically are obviously the former case and those were widely celebrated).