the unaddressed plot hole in isekai's

Y'all ever wonder what the original host of whichever body the mc possesses is doing? What makes the MC so important that they're the only one whose wish gets fulfilled or are randomly transported into another world. What right does the MC have to live someone else's life like that? Why do they feel no guilt? They usually transport into novels where they read of the character's fate so they know the body doesn't belong to them. Even if they transmigrate into a so called villains body how is that justification for living someone else's life? How is it justification for stealing their family and friends? How do they have no mental breakdown's or not go insane?
I doubt the original hosts of the bodies wanted someone else to live their lives. I mean sure some of books have addressed it nicely but the majority don't. Also, I'll read isekai's but this problem has been bothering me quite a bit.
I'd say, "Trash of the Count's Family," has done the best job addressing this. And a side note for people who have read the novel and are caught up on it, y'all ever wonder when Raon's attribute/power will come into hand? I'm not going to say exactly what is it. However for those who do know it, don't you think it hasn't been addressed enough and the time theme going on could have something to do with it?