Glad to know I'm not the only person who is looking at Ironwood and completely understanding his motivations here. There is absolutely no reason for CRWBY to backpedal on this, they wrote a genuinely good character arc and it works perfectly.
Ironwood is the Tin Man, therefore he has no heart. That's clearly what they were going for with this, but in the context of a military general who has been pushed to the brink, who is also a leader of a whole country, yeah. He's making tough decisions. Abandoning Mantle to save Remnant is at least a plausible decision to make, and arguing against it because "but we have to save every last person!" makes Ruby and her crew look like naive children who are brand new to the war, which is what they are. Both parties are in the right and in the wrong for different reasons. It's fantastic, I haven't been this excited for a season of RWBY since I saw Qrow's drinking problem in the opening of Volume 6.
When you think about it, James's character arc is very much the same as Qrow's, but going in a different direction. Both men devoted their lives to fighting against Salem, making sacrifices and keeping secrets for Ozpin. Neither of them was told that Salem was immortal, and when they found out, they felt betrayed. While Qrow spiraled into depression at the idea that his best friend never trusted him with the truth, James was spurred to action. Clearly, the way Ozma had been handling things all this time wasn't working. And his determination to share Salem with the world makes perfect sense, how else would Remnant eventually become united to pass the test of the Gods?
Is James in a bad situation with Mantle? Absolutely. But Salem is on his doorstep. He has to make tough calls and prioritize, and he has done so. Hell, for all we know, he did it knowing full well that if he directed his attention to Atlas, RWBY would run off and play hero with Mantle anyway, and wouldn't even need his help.
It really is amazing that the fans of this show are so inundated with excess empathy that they think a general and a superhero are interchangeable. No, you cannot save everyone, and if you try to save everyone, you are a moron who is going to lose more than you could have.