What a ing dumb thing to say... The ability for teams to trade players to other teams is explicitly written on the contract the players (and teams) sign. There's always obligations and things to be earned for fulfilling them (you think contracts don't also stipulate that players have to play games, be at practice, etc?). Teams absolutely "respect" contracts and if they broke them, the NBPA would be on their asses about it.
What Nephew did (sit out a season he was paid for, force a trade, and all the shenanigans that followed) is not contemplated in the contract, because they have specific lengths to be fulfilled. It's also the magic that makes players retain their salaries and contract duration if/when they're traded. You might want to look for another example for your stupid point.
E: players can literally have No Trade Clauses weaved into their contracts under the right cir stances... Just a re ed comment all around, tbh