They're thinking of the children, after all.

Sony are the ones being left behind with this decision while Nintendo/Microsoft/PC move forward. Nintendo and Microsoft actually gain a huge advantage because of it.  It's Sony that is the one being left out, not the other way around. 

It just makes it even more funny to see people desperately trying to spin this as a good thing for Sony knowing that. It sucks for the tons of people on PS4 that want Cross-Play and Sony is holding them back, but when they make decisions like this and you see the amount of people that already jump to their defense no matter what it's not surprising that Sony still keeps going with stuff like this. 

Instead of looking at the advantages and benefits it could have for the PS4 playerbase (which a lot of them DO want Cross-play too) all some people can do is look at it as Sony "giving" something else to its competitors (when that's not even the case since Nintendo and Microsoft are just moving on with it without them now lol). Because in their minds heaven forbid Sony ever not be on top for one second in something despite what their consumers want, that's all that matters to them.