Why can't Clark just be someone who develops an interest in journalism, though? A character doesn't lack a personality just because they're not given a personality trait you've come to expect. His personality was that he was adrift, trying to figure out who he was and what he wanted. In other words, Clark can start out as someone who sees journalism as a means to an end for his personal practical purposes, yet grow to see its value.
In BvS, Clark initially goes to Gotham to talk to Kahina. However, when he's informed she's not there and another resident starts talking about the new, more brutal, Batman, he shifts focus away from himself. Clark doesn't use his Batman investigation for selfish reasons. Far from it. He doesn't know that Batman even has a grudge against him. All he knows is that because he is public, politicians and other citizens are given a platform to air their grievances.
He seeks Kahina out because she accuses Superman of answering to no one, and ultimately he answers to Finch's committee. However, while in Gotham, he discovers Batman's in the shadows operations as a vigilante among the poor and disenfranchised have allowed his actions to go largely unquestioned, and thus Clark comes to realize how he can use his position to give them a voice. He repeatedly defies Perry's cynicism and attempts to refocus his efforts on more trivial pursuits, to champion the merits of journalism and his own investigation.
I like takes on Clark where his interest in journalism is something that he has from an early age or at least as a teen or young adult, but it's hardly the most consistent trait of his and hardly something that can't be explored in different, yet equally valid, ways that show him having a genuine passion for the profession.
