I'm really trying to understand. So I encounter a god who says he's the one true God. We've established that. It is me he's talking to. I have an idea about what I think God is based on my belief in the Bible. This god is not like that idea at all. The Bible says God - the one true God - is love. I believe that. But in this scenario, this God that I'm speaking with is NOT like what I believe. Therefore, this God is hatred.
I use the same formula for all the attributes of God that I believe Him to possess. I believe them because I believe the Bible, and the Bible speaks of MANY attributes of God. I can't objectively SEE such attributes as love, justice, mercy, forgiveness...maybe if this God were to give Variant's kitty up there a nice warm hug, that would be a demonstration of love, but since this thing is and represents everything I dislike, it does not possess the attribute of "love", because I dislike absolute hatred. It would be more likely to kill the kitty.
Ultimately, if it turns out that the real God is a mean, unfair, vicious, contemptuous, apathetic, selfish, unkind, spiteful entity, I suppose would likely do what just about anybody would...I would descend into complete madness. The very notion that this evil god created everything including man's concept of "good" just to snatch it all away and force His people to choose between torture and torture would be the very definition of insanity. What would YOU do?