First the fact Jimmy Butler got 9 first team votes is a joke and that impacted him making it at all.
Second the fact voters voted for Tatum at both spots reduced the amount of votes he could get at forward.
Tatum had a better year than Paul George as well and he made 3rd team as well.
Tatum lost serious coin because this process is done in a stupid manner.
I mean, yeah, of course Butler receiving first team votes helped him make it lol. That is pretty nuts though. I can only assume it must have been some of the advanced stats guys; Butler's metrics were through the roof this year.
At any rate, Tatum receiving votes at guard (if he did; we don't actually know the split by position as far as I know) would help. It's not like the NBA says Tatum had 69 points at forward and 65 at guard, and therefore he ended up with just 69 points at forward. They add up the player's total votes and then pretend they all came from the position that they received the most votes in.
Simple fact is that voters could list Tatum at guard or forward and they simply didn't vote for him at either. Even if you removed all of Butler's 1st team votes, and kept Tatum's 1st team votes (which are also ridiculous), Butler still would have made it over Tatum.
I understand the argument that he maybe should have received more votes than Butler, but that's a totally different argument than saying the system itself screwed him, which it didn't.
Also, again, Butler is in the same boat as Tatum where he's listed at both guard and forward. I would bet that Butler received more votes at guard than Tatum did; if anything, Butler's eligibility at guard might have ultimately been the reason he ended up with more votes than Tatum because I think voters were much more likely to treat Butler as a guard than Tatum and guard was the weaker position this year.