I agree that Sony is being dumb by not allowing crossplay, and I think Sony looks worse than NINTENDO of all people when it comes to this specific online matter. But if I'm running security on an online service, I don't give a shit how many assurances some outside service gives me about how they're not going to put "the kids" in danger or whatever. I don't give a shit if some other company says "oh we believe Microsoft." Unless we have a specific business arrangement, I'm not going to take your promises as given. I'm just not. Even if I think you'll try your best to keep them.
Yes, blame Sony for not brokering the business arrangement. I don't know how hard Microsoft tried to get Sony to sign on, and I don't know how hard Sony tried to make things work. But to act all hurt because "we would never hurt the kids, how dare you Sony" smells faintly of bullshit, regardless of how right Spencer is otherwise.