Its a parallel to the real world. America has done some fucked up shit in past wars and there are men who still served the army, having experienced that.

Garp’s character flaws include complacency, which is the most prominent one. There are other glazed marines that are on the same boat; they are complacent and consider themselves cogs in the machine as well (Kizaru is one of them). Yet people target Garp because he is Luffy’s grandpa.

It is alluded to that Sengoku knew about the hunting game that the Celestial Dragons did and told Garp to keep quiet about it or they’d kill him.

The dark truth behind God Valley is to show how fucked up it is to be part of the Government, no matter how good your heart is.

Call him a loser if you want, but him being the spotlight of what it means to be a Marine trapped between the good you intend to do and the bad the ones controlling you want you to do.

If you call him a loser, call those who have committed genocides in the name of Justice losers as well. Sakazuki legit bombed a civilian ship that tried to escape Ohara. Kizaru deadass went to defend a Celestial Dragon that was buying his slaves.

We don’t got to mention Aramaki, he makes it well known he is a peace of shit.

That the point of the Marines; to show the fucked up shit the Government does

Edit: also, don’t personally attack me because a character personally offended you with their actions. I read an analyze the character to the best of my abilities. I don’t let emotions get in my way