Just a reminder: GPII is listed on the Warriors' injury report as suffering from "Adductor soreness".  To my knowledge the Warriors did not release the results of the GPII physical, they just said he failed it.  So, we're left to fill in the blanks as to "why?" on our own.  In light of those facts, let's please be clear about the "playing through injury" angle.  We have zero evidence that GPII is actually injured.  Sore?  Okay.  Not 100%?  I'll buy it.  Injured and being forced by us to put his career at risk by drugging up and playing?  Not a chance. 
Sources close to the Warriors have stated that they never seriously considered rescinding the trade, and their first attempt was to try to claw back some of the trade compensation, so let's not pretend they're just fighting for Truth and Justice.  They wanted GPII more than we wanted to let him go, so we (for once) got the better end of a trade deal.  Compared to the Clippers and Pels who fleeced us, this trade marked one of the first times we clearly got the better end of a deal.  GMs have egos, and it probably stings a little.   The injury story was a convenient one, but it got out of hand.  Now their only way out is to double down.