He never says he doesn't include nintendo in his defense. He is talking in general.

Also isnt the amiibo dlc just the same exact missions in Story mode, but played with a different weapon? (each amiibo unlocks 1 costume each, but thats significantly small to be mad about unless you like that school girl outfit :p)

You clearly haven't played the game and predecessors. not only  you came with the untrue "like around 40 of which are returning cast, most of whom has the same moveset and animations from previous titles.", you ignore that everything is adjusted and balanced from one game to the other.

I really don't think that amiibo are anywhere close to being on the level of the things that Sakurai is talking about. You want to talk about the implementation in Splatoon? Okay, you unlock challenges which are simply playing through story levels with a specific weapon and what seems to be single player exclusive costumes. You really aren't missing much of anything, as the primary use of amiibo are as collectables.

EDIT: Jim Sterling made a video about amiibo which I think is quite good:

https://www.youtube.com/watch?v=ZIaIbkpMjho

It's not a "bonus".  It's not there because Nintendo just wants to be nice.  It's there as an enticement to BUY AMIIBOS.  It's there to earn MONEY.  It's DLC they worked on to prepare for DAY ONE.  It's the "easiest way to make money."  

The only difference between this and on-disc Horse Armor is that this is bloody expensive.  The convoluted logic people are trying to perform in order to make Nintendo look innocent of trying to make money is astonishing.

If the Amiibo DLC was avaliable WITHOUT having to purchase an expensive toy, it would still be Day One DLC but it would make them look far less predatory.

It's hard to tell if he is or is not including Nintendo as following the "easiest way to make money" in that blurb, which is why I phrased my post the way I did.  If he is, then good for him for admiting it.

It still doesn't change the fact that many people who were universally against Day One DLC are now throwing out excuses and justifications for Day One DLC.

No, there's only mewtwo, lucas and ???. And the price includes months of extra work.

The Mii costumes are being charged for. That's bad DLC, Sakurai.

With regards ti the 100% at the time of release issue, doesn't Splatoon have a multiplayer mode scheduled to come at a later time? I think it will be free but still flies in the face of what he is saying.

I think you are stretching the argument a bit...Day One DLC as it exists now is generally considered to be one of the more minor issues, if it is considered an issue at all. When Day One DLC is extremely minor stuff like cosmetics, there is really no reason to complain about it and that is really all it is in Splatoon (as I described above, the challenges add nothing and the costumes are costmetic and seemingly single player only).

What I read Sakurai to be talking about are the instances in which it feels as if a meaningful part of the game has been removed, from important story content, to important characters or actually finishing the base game. Cosmetics aren't the issue and if anyone makes them out to be, that seems like an incredibly petty complaint.

As you said, it is free. It really has nothing to do with what he is saying.

Also, that mode has been explained. There is no sense in releasing a "hardcore" mode, before the playerbase gets to that level and that is what this multiplayer mode is. Once a certain amount of people get to the level required to play this mode, it will unlock. I really see no way in which this could be considered objectionable.

How is this Day 1 DLC? Those are physical goods you can get if you want. They do have extra costumes in them, but they are collectable goods you can get or not. I don`t really see how this is Day 1 DLC.