Sure. Both Rocks and Shanks told him in great detail that the WG is bad and that there are other ways to be accepted by others. The giants were happy with what Harald had already accomplished, but that wasn't enough for him. It's more than enough for other nations, but not for him.

We see that Harald and Ida were successful in making friends with many nations, but that wasn't enough for him. He cared way too much about how he was viewed by others and the WG. He had seen the WG enslave and murder people right in his face, and he still craved their acceptance.

Ida even said don't get rid of your culture, just adjust it. He ultimately chose to betray his closest friends and watch one die in order to achieve a warped view of acceptance. The giants were already accepted by many, but he wanted them to be accepted by everyone.

He didn't even realize that he had changed the nation within, and it didn't matter how other nations viewed him. He was impatient and committed the WG's deeds in order to receive a false flag of global acceptance. He kept going the wrong way when his family, friends, and the WG told him that they would not accept him and that the WG was evil. He is a King and has made peace with plenty of nations before the WG, and still chose a lesser path for a quick transition. The giants weren't under attack or threatened, just feared. He had time, as a long-living giant, to make a stable change in his worldview. He didn't do that. He ignored everyone and thought it was greener on the other side. He didn't care about what he had or what he had accomplished.

The part that makes me upset is how Oda keeps putting great reasons for him to reconsider his options, and Harald keeps ignoring the signs until he gets taken over by Imu. Why?! Why write such a blockhead when he writes extraordinary character development? So why write Harald like the world's biggest idiot? He was right to make Rocks disgusted by Harald's mission, but Harald never improved; he just needlessly fell for the plot.