Is telling them what the NX is = sales?
Because they sure as hell have to tell them what exactly they are investing their money in, don't they? Holy hell...

Everything is correlated to sales. But it's not only sales figures specifically.
Release dates are one such thing. So is the NX concept.

Yes... that's what I'm saying.

R&D for consoles takes several years. (That's plural.)
They asked for R&D money for NX years ago. At an investors meeting.
When the investors give them their money, they are given a projection of when they will start to get a return on their investment. Among many other details.

Here, this should help:

Nintendo: We are creating a new console with a new concept. A completely new platform.
Investors: Cool. What will it be?
Nintendo: We won't say.
Investors: When can we expect a return on our investnent?
Nintendo: We won't say.
Investors: TAKE MY MONEY!

Yeah, that sounds like business alright.

Kimishima's quote regarding Nintendo-like profits in the fiscal year ending in March 2017 can be found in their transcript of the investors meeting that took place in late January/early February 2016. The absence of Nintendo-like profits can be looked up on Nintendo's forecast that was made public earlier this week; they are projecting less than half of Nintendo-like profits (a term that is defined as 100 billion yen).

The most plausible explanation for that change in outlook is an NX delay. Missing the holiday season as well as a reduced availability of roughly four months. A November launch would have given NX roughly 4.5 months to contribute to Nintendo's profits while the actual March launch will give it one month at best.

No one is going to buy major shares in a company unless they are filled in on what's going on, and where their investments are going.

And as for you theory on people buying shares to get info on NX, so they can spread it. It takes many millions to get a seat at that table. You seriously think there are people who would spend millions to get info on NX just to spread it?
First of all, when you spread info on it, then you risk losing money you've invested, as competitors can beat you to the punch. Secondly, unless you go public with your name, your info will be treated as a rumor anyway. But more importantly, no one is going to spend millions for that info.

Then why not release it holiday 2017?

how is that question at all related to what he said?

Because that would result in Nintendo holding back lots of NX games at a time when the 3DS and Wii U wouldn't be generating much revenue anymore. If Nintendo doesn't sell new products for an extended period of time, they'll have a hard time to turn a profit. It doesn't make sense to delay NX for another eight months when it's ready to go. A launch in March 2017 will allow NX to contribute to Nintendo's bottom line for the full twelve months of the fiscal year ending in March 2018. A November 2017 launch would reduce that number to 4.5 months.

The only reason why NX would be delayed further is that game development falls behind schedule. A holiday launch might be preferable, but it's not important enough to opt for a long delay for the sole reason of having a holiday launch. Regardless of when a video game system launches, eventually it will have to sell during non-holiday months.