You mean broken games like Driveclub and AC:U? Those didn't get glowing reviews. Halo MCM was an outlier because the reviewers played in a controlled environment. People often call out companies for On-disc DLC. There are people who call out Nintendo for that too but from what I've seen, Nintendo generally doesn't get as much backlash for stuff like this. Feel free to not believe me but I know what I see.
Maybe people call companies out for on-disc DLC because the DLC in question has a cost associated with it?
That companies cut out content to make an extra dollar?
Evolve reviewed decently despite the DLC controversy it has a similar concept as Splatoon - roll out more content as time goes by. But at the same time it over viewed that you would pay for certain content.
For Splatoon we don't know other than the Ranked mode whether there is any on-disk DLC. I expect the majority of additional maps to be there for example, but the rest of the content like the new modes Tower Defense/Rainmaker those are obviously getting patched in August.
It's quite simple for me judging from the Devs the game simply has a lot of things they couldn't include in time and are still working on.
If people review the game badly because it's lacking content it's perfectly understandable.
I just don't see what about the plans of future patches similar to things which people got for FREE on MK8 like 200CC would cause an outrage. I don't think you understand that it's not the concept of DLC I have a problem with, it's the pricing structure. Most devs price their DLC idiotically or lock content behind paid DLCs at launch. Splatoon has amiibos which unlock costumes but don't lock away any content. All the weapons you get from Amiibos are in-game, and all the single player missions are in-game.