Nothing wrong with Sony protecting their business interests, but if that's the case then they might as well drop their "For the players" slogan

Sure. I would be all for that. If you were trying to goade me into a negative reaction, you failed though. I am a PC gamer. ;)

I don't care about Sony's business. I don't care about Microsoft's business. I am a consumer, neither are actually my problem.

False. And a bad example if Minecraft is your basis.

The Playstation 4 will have the worst version of the game.
In-case you aren't aware... Minecraft is one of the biggest franchises in video gaming history, ever. Not having it up to parity with the PC, Xbox One, Switch, Mobile and so on, places the Playstation 4 at a distinct disadvantage... And if that is the case, I hope Sony looses a few sales from it.

Clearly Nintendo doesn't agree with your hypothesis.

Microsoft does have the better track record when it comes to security anyway.

Indeed. Sony is being Anti-Consumer. They deserve ridicule on this.

Ignoring your ad-hominem, it is indeed political.  Sony are using pointless excuses to justify their reasoning.
Sony is being Anti-Consumer, you need to come to terms with that.
These are multi-billion dollar companies, they don't care about you as an individual, they care about money. - They won't send you cake and flowers for buying their products, so being "loyal" to them is stupid.

Since Minecraft is basically a MS first party title, if PS agreed to new Minecraft and connecting through Live, but said in return we want to put say Uncharted 4 (or another first party title) on XB1 and those players must be able to connect through PSN, would MS allow it, and would it be a good thing for PS?

I think unless PS was able to put multiple titles on XB1 that have access to PSN, to match up somewhat more evenly with Minecraft's popularity, that PS wouldn't even consider it. Even then, it may hinder PS4 sales more than help.

if they make the signin to microsoft optional its win-win because people can opt to go sony's way or opt to go cross-platform and play with everyone, which is the best thing for everyone

So it's not your problem to change from: playing with others with your own gamertag, being able to find the people you know through their gamertag, to creating a new gamertag none of your friends know, under new rules, even if you're still playing with the exact same userbase? Isn't that slightly inconvenient?

Why would it have the worst version of the game? It has a large userbase, MS gains much more than Sony by selling the game and its DLC on ps4. Why would Sony care to lose out on the much smaller platform royalty. Those users will simply buy something else, maybe even a Sony game that gives them 100% of the revenue. Sure Minecraft is popular, but it's not a system seller or deal breaker. It hasn't been at parity with the PC for the longest time, has never seemed to hurt it. MS is the one that will lose the most by neglecting the ps4 version.

This thread is funny "Sony should be thankful MS still allows Minecraft on the ps4" MS is the one who should be thankful for getting all those ps4 users to  enjoy Minecraft who then get tempted to buy all kinds of Minecraft merchandise as well as other versions. But sure, one corporation holds a grudge while the other tries to spread the love of Minecraft for all. It's simply business. MS can save costs with a unified userbase and attract new people into XBL. Sony loses control over the multiplayer portion while seeing no extra income from this move. MS will need to sweeten the deal if they want this to happen.

Didn't Sony try to go cross platform last gen and Microsoft denied them because they were winning? Sometimes the tables turn.

Sony wants to keep its closed and proprietary ecosystem, because it can't expand it beyond PS, OTOH MS wants to expand its own everywhere, because it never abandoned its idea of a proprietary whole internet.
Both visions are closed and proprietary, but MS one is far more dangerous, just because MS has the resources and a wider existing ecosystem, outside of consoles, to try and carry it out. Luckily Android and iOS can prevent a global MS monopoly to happen outside of PC, because if Sony and Nintendo were the only obstacles, they'd be either crushed or marginalised.
Minecraft new offer is just a little creepy move if taken alone, bust it must be framed in a far bigger and more worrying picture.
Neither Sony nor MS are innocent, but MS is more dangerous.

It's just common business sense. Of course Sony doesn't want to herd their huge userbase into the ecosystem of their direct rival. It would be stupid and MS has much more to gain than Sony in this thing. Gamers complain, but gamers are not businessmen.

Rocket Leauge on PS4 already has cross play with PC!

Linking accounts (like U-Play, Origin, Steam, etc) to your PSN account isn't the same as loging directly into another network on a PlayStation device.

https://support.steampowered.com/kb_article.php?ref=5477-WPJM-9388

Portal 2's Steam/PSN Account link process is still outlined even though it is no longer supported. Some helpful information is transmitted between the services live including "Steam Achievements".

These accounts are linked to PSN, like Origin can be linked to PSN, like U-Play can be linked to PSN... What MS wants is to bypass PSN and Nintendo Network altogether to control everything. Even though Steam allowed all manner of things to be synchronized between these two independent services including achievements and likely DLC, MS wants direct control.

Not a good idea to allow this in my opinion. But Nintendo has already opened Pandora's box by letting MS egress into their online services. Do you really want EA to control Xbox Live or Steam?

Think about that really hard now...

Then why would you expect Sony to allow any other platform holder, publisher or developer to control how or when PSN is going to be used on their own systems?

Was about to explain this, I Could not have said this better myself