This stat does not mean what you think it means. Anyone who uses a single game +/- to compare two players either doesn't understand what the stat means, has a specific agenda, or most often, both.
Ed Davis was -36 tonight. So, does that "prove" he's even worse than Meyers?
Hell no it doesn't. I get that everyone hates Meyers, thinks he sucks and is excited about Nurkic, but using this stat, in this way, is not valid.
+/- is not an individual stat, especially for a one game sample size. It is highly dependent on the other 9 players on the court. If one, or more, of your teammates has a bad shooting night, or plays shitty defense, it negatively impacts your +/-, even if you're ballin' your ass off. The reverse is also true. If one of your teammates comes out and lights it up and goes 18-22, you're going to have a damn fine +/- for that game, even if you individually went 0-4 with 1 point and 2 rebounds in 36 minutes. Likewise, it is dependent on the quality of the opposition's play. If a player on the other team is lighting up one of your teammates, your +/- suffers through no fault of your own.
So, you have to ask yourself, why did both Meyers and Ed have such a low +/- tonight. In a nut shell, they both started and were both in at the start of the second half, when their teammates couldn't make a shot. Just go back and look at the first 7 minutes of the game, Dame and C.J. were a combined 0-9 from the field and Portland was down 18-8. Meyers and Ed actually played well during that stretch, but they both get stuck with -10 in the +/- column for those 7 minutes.
I'm not saying Meyers doesn't suck Nor, am I saying, Nurkic isn't better. What I am saying is using a single game sample of +/- to prove either premise is a misuse/misunderstanding of the stat.
BNM