Logically speaking, yeah, they really can't be viewed in the same way.
The first problem is that, in the NBA example, the reason why we expect the sportsbooks to give some leeway is because we are talking about odds, which are a marketplace. And there is always going to be a range of available prices in that marketplace. If we allow books to void bets based on a price difference of 5%, then we are giving them license to (unprovably) lie and essentially void any wager they want, giving them a severely unfair advantage. That conundrum doesn't exist here. Slots are supposed to be -EV, period. We all know that intuitively.
The second problem is that we aren't talking about a single bet, as in your NBA game example. We are talking about a system which can be used over and over again, so aggregate value (total $ profit) is only limited by spins. A slot with EV of +150% per spin and a slot with EV of only +0.01% per spin can both equate to millions of dollars if given enough time. I'm sure that a casino would go to court over both and argue that the player took advantage of a flaw. And unlike the NBA game, this flaw can be mathematically proven.
Should they pay some of these players out of goodwill or for
PR purposes? That's a different, difficult question to answer.