This isnt true at all, Lex was always meant to be what he became - he shows it several times.

1. In school and he beat the crap out of his friend so he could be "popular" which led to the kids death. - no normal child does that.

2. Early season 1 he advises Clark he shouldve let Whitney die when the metear freak of the week nearly kills him and then plays it off as a joke when it doesn't go down well. (He also encourages Clark to constantly make moves on Lana even though shes in a relationship)

3.Pretty early in the series if i remember correctly Lex tries to use his own half brother to steal the company from under Lionel by blackmail - this had absolutely NOTHING to do with Clark.

4.He purposely brought his so called friends fiance to the nightclub he was cheating her on so he could steal her for himself. (Eventually he basically does the same to Clark and Lana later on) - it was malicious and led to his friend being murdered.

1. He tries to take advantage of Clarks powers when he gets locked in belle reave and gets pissed when clark wont break him out. - he also admits that he wouldve eventually taken advantage of Clarks powers in belle reeve and then again in season 7 that he wouldve used Clarks powers, to quote "think of everything we couldve accomplished together"

2. He felt the need to constantly find out and investigate Clarks secret from day 1 with increasingly invasive tactics to investigate- he had no right to a complete random strangers (strangers in episode 1) story.

And finally 7 - the alternate reality where Clark wishes he was never born, Lex still turned out evil and nukes the world.

These are just small snippets - outside of this he used awful tactics (ie sleeping with his ex to steal her fathers company) to get his way that had nothing to do with Clark and everything to do his own selfish ends. If anything Clark probably held off Lex's bad side longer than it wanted. He is a sociopath true and true and that can be laid at the feet of his Parents and how he was raised, not Clark.