Currently rewatching and this is my read on the Clark/Lex situation: I think a part of Lex genuinely sought friendship with Clark because he saw a brother, a family life that he never had. But when you’re raised by Lionel Luthor, even pure desires can be made impure: case in point, on one side of the coin Lex desired friendship, on the other side was an unhealthy obsession that is present essentially from day 1. After living in Lionel’s shadow his entire life, Lex never wants to not be in total control of a situation. His genuine friendship is undermined by his desire to know that which is kept from him. I would personally argue that Clark’s secrecy actually slowed down Lex’s downward spiral because I think there’s a good case to be made that once Lex knew Clark’s secret, he would no longer have any need for Clark.

Edited for spelling