https://imgur.com/gallery/yn8AqPY
They have, clearly, in the game guide
It could, perhaps, be expounded upon and made even more clearer with some examples, but they state “with each 1% negative resistance increasing damage taken by 1%” , the corollary of which is “with each 1% positive resistance reducing damage taken by 1%”
Also, if this game did everything that “every other ARPG” did, then it couldn’t make itself distinct. Having a system with the same name as another ARPG doesn’t mean that they should work exactly the same. Or should they take the Ward mechanic in this game (which existed before it did in POE) and make it function the same way as it does in that game?