There's two factors that I can see:
1. Trump thinks every deal has "winners" and "losers." Since other countries clearly see the Paris agreement as a "win" for them, that means that they must think it's a "loss" for the US. Hence, the US is pulling out so that they don't "lose."
2. Trump hates deals that he doesn't think of. There was one bankruptcy he was involved in where an arrangement was reached that was good for him, good for his creditors, and allowed the workers at the affected business to keep their jobs. He nixed it because it wasn't his idea.