I'd go as far to say we don't really know everything that goes on behind the scenes, so in all honesty, we don't know who is playing the relationship card or not. Yeah, the WWE does it themselves, but I am sure that plenty of the wrestlers do too. But we don't really know.
The idea that a wrestler should know their place and role and keep quiet is asinine. It's their career and how they are treated in the WWE will directly affect how they might be viewed in post WWE careers. If they don't like their place or their booking, they should feel free to speak out. If fans don't like it, you're not forced to listen to it. You're not forced to read it. However, they have every right to say whatever the hell they want about it and I support that.
If Nia feels her WWE career is not going to the way she wants it to, she has every right to bitch about it AS MUCH as the WWE has every right to book her to lose. She is not entitled to a good push. She is not entitled to a championship reign. She is not entitled to even be on TV. What she is entitled to is to express her pleasure or displeasure in such and we are entitled to ignore it if it bothers us.
Personally, I could see why she is upset. They push her as a monster who loses all the time. They keep on making her Alex Bliss's sidekick. Hell, that alone would piss me off. If she thinks she would fare better in other places for a lower paycheck, she is entitled to do that as well once her contract is over.