I know right, got bit by this several times this year on leovegas, stakemania family casinos etc. Always feel a bit gutted to say have $1000 balance then beat the wager and see it drop to a fraction of that.
That being said as the players thats on us for accepting those terms and I do find I lose less money playing such high deposit % bonus offers as the wagering eats up my play time I'm depositing less. Beating a 35-45x wager feels like an achievement given the odds of doing so because you have to run so hot to pull it off. I essentially write off those deposits and any cashout is a win.