The crux of the argument, and the part that no one can seem to move past, is that there are people who consider it fundamental to the experience and those that don't.
I personally see voice chat as a largely supplemental thing and something that would just rob some of my connection that I'd rather use for the game I'm playing, but I can understand that there are those who want it.
And no one would argue with your desire to have it if you didn't drape it in all this other bullshit.
"It's a standard feature/it's 2015/etc" ignores all the games that exist without it, Nintendo excluded. The majority of iOS/Android co-op games have zero voice chat options. ZERO. Even the largest among them, Clash of Clans, requires 3rd-party chat options. So unless you're going to claim that they aren't games like so many people on GAF believe to be true but are too afraid to say so, it's hardly a standard feature. It's a NICE feature, but "standard" is stretching the boundaries of reason.
"But there will be no community now" is a strange argument. Does Mario Kart 8 not have an online community? It still seems to have quite a number of people playing it online, so you'll forgive me if I'm confused by how one feature omission means there can't be an online community when there are plenty of examples that show that to be untrue.
"Nintendo is behind the times/Nintendo gonna Nintendo/etc." OK, so what do you expect to do about it? I've seen this discussion repeated ad infinitum and it leads me to believe you'd all rather bitch about it on GAF and make every thread in every game that doesn't include it into some sort of user referendum. But GAF isn't Nintendo, what do you expect people here to do about it? Of course there's going to be people who don't give a shit about its omission, rationalize it away or discuss the methodology behind its exclusion, because that's all GAF is capable of doing and some people just don't care. Making it a fanboy issue if someone disagrees with you gets NOTHING done. Period.
If you want it to change and there's seemingly enough of you who want it to, take it up with the people who actually can do something to change it. Use this thread or any other of the many that preceded it to rally support and make it known to the company that made this decision that you don't find it acceptable. The fact that hasn't happened yet tells me that it's not as important as it's being made out to be, especially when we're looking at a Nintendo that has become more open to feedback from players than ever. Please prove me wrong if I'm mistaken by taking an actual action, because passive-agressive moaning about it gets really tiresome. I see it in other threads, as well, and it's equally meaningless there.
tl;dr version:
Be honest about what you're discussing. Instead of making it about some obvious failure, just say you're disappointed; more people are likely to find your opinion agreeable. The indignation people are spouting doesn't help their point.
And for god sake, if it's a big deal, fucking DO SOMETHING ABOUT IT. Do something to improve the situation with the games you enjoy instead of the stock "vote with your dollars" bullshit answer or being an incessant whiny child about it.