Well there are a couple differences between Krelian/Sophia and Shuyin/Lenne....

1. Not a big difference but the former is unrequited; Sophia only ever loved Lacan.
2. Krelian's plan kinda worked. He ascended to the the higher dimension with the Existence. Shuyin had his doomsday weapon destroyed. He had no real chance of destroying the world after that.

So yeah Shuyin lacked conviction when his conviction manifested in front of him and told him to knock it off.

But this all seems like we just have different conclusions of the same events and you can't really convince other people of your perspective..why it's your perspective ya know?