I'll just give out a general rebuttal rather than reply individually. I think Nintendo hurts the industry based on the following:

1. Wii almost killed what other more serious companies had tried to do for the video game medium. It forced both Sony and MS to divert resources into motion controllers which invariably failed. I mean Kinect almost single-handedly sunk the XB1.

2. In the same wake, the Wii U gamepad has done nothing to gaming. In fact, it has just alienated gamers. We don't want gimmicks. We want a true gaming revolution like VR. The medium of video games as an art channel is held back by Nintendo's insistence on weak hardware. Graphics will be a defining factor in the industry. With better graphics we will have better immersion. For example we can express human emotions better and more clearly with advanced graphics.

3. It forces consumers to purchase two consoles, one for HD, third-party games, and one to almost exclusively play Nintendo games only. It's like buying two very expensive blu-ray players because one only plays studio exclusives. And the same argument does NOT apply to PS4 v XB1 because their value propositions are far superior to the Wii U alone. And you don't have to buy both but you have to buy a Wii U and something else if you want third party games.

4. In the same wake as #3, Nintendo has again alienated consumers by money hatting Bayonetta 2. Keeping an otherwise excellent game out of reach for millions. This very game could have been published by Nintendo on XB1 and PS4 if they went third party.

Wow, a nearly identical reply to the other one I got.  You guys are a clever bunch.

I could just as easily say that if you are finding good reasons, you need to scan harder.  And it would be no less or more stupid.

For both of these points, there is no force at all.  You aren't required to entertain yourself with video games.  Also, competition generally keeps costs down and the business from becoming stagnant.  Do you believe that if Nintendo went third party and eventually there was only one console they wouldn't charge a lot more than just $60 per game at that point?

There's plenty of competition. MS is here to stay as evident by the fact they're willing and able to almost give away their console to stay relevant. MS and Sony move the industry forward with a singular vision of hardware. Nintendo does the opposite and as evidenced with the Wii fad it's harmful. 

There will never be just one console. Apple, Google or Valve would enter the market to fill that spot. 

"Look at Sega" is literally the worst point you can make against Nintendo going third party. Sega didn't turn to shit because they went third party, they had to go third party because they were never really very good to begin with.

Sega is a shitty game company, plain and simple, they have hardly any IPs of value, they don't know what to do with the few valuable IPs they have and everytime they have something good on their hands they fuck it up almost immediately.

I hope some of you people realize that saying that the only thing that's standing in the way of Nintendo becoming the next Sega is their proprietary hardware, is one of the biggest insults you could throw at Nintendo.

Serious question:
Why buy any console and pay hundreds of $/€ for online if you can get almost every game on PC? And by the way more exclusives?
So MS/Sony are 'forcing' me as well to buy their consoles just for a few exclusives? And online fee?

Yes, there's that nice games with gold/PS+ argument. Funny thing, espacially with GwG is, there has been no interesting game for me i hadn't bought before until now. And PS+ on PS4, wich is more or less mandatory for online, doesn't have as good deals as PS+ on Vita and PS3.

Why shouldn't they?  There is a real risk of hacked hardware with 3rd parties working on your hardware.

The only way to safely do it is a virtual machine that separates programmers from the bare metal hardware.  VM's demand significant resources and they would be very complex to just start doing for a console.(you have to publish virtual versions of the hardware into the VM.)

Trust me when I say 3rd party makes gaming companies want to vomit.

Well, based on your statement of Nintendo forcing people to buy two consoles it was only logical for me to infer that once they go third party you would want the other console maker of your choice to also go third party to fit your desire to only buy the one console.  Based on that, I supplied the comment that fit the scenario.  My mistake.

Without Nintendo being a "competitor", Microsoft and Sony may begin inflating and deflating prices like crazy while throwing cash around to secure exclusive content and stuff.

Alright, we each got our snarky point across. Move on.