Um...his motivations in the game were the same, just without the extra backstory. There he claimed humans were selfish, greedy people who did nothing but compete and take things for themselves, the same as he explains in the anime. The anime just elaborates that he tried to help humanity only to be treated like this.This wasn't enough. The games version was terrible, but they tried harder with Lysandre's motivations.
About the only depth Lysandre got in the games was his lamenting that Pokemon would also have to die, but at the same time the anime made it clear that before he was forced on his backup plan, he wanted to guide the world to a better future using people like Ash, which is very different from the hypocritical "chosen elite" that were actually the selfish humans he hated so much.
I don't know where you get the idea game Lysandre was any different since he was so barebones.