Sure, it could be a coloring error. I admit that. But why automatically do a bad faith reading on Cap is the thing I was mostly trying to point out. Is he a different kind of friend then Jim? Sure. Jim's more in-touch with his sensitive side than either Steve or Namor or even Bucky are. From Steve Namor gets blunt honesty, Steve's the type of friend who will tell you straight-up when you're being an idiot, but he'd also take a bullet for you in a heartbeat. From Jim comes the sympathy and more compassionate nature. They are different. That's why they make a good team *shrug*. If they were all the same they wouldn't have pushed each other to be as effective as they were as Invaders. Doesn't mean Steve doesn't care. Obviously he does, he dropped everything to run to Namor despite Tony beseeching him not to and despite the fact that the Avengers chair, T'Challa, probably will not be too happy with Steve for abandoning his post when there is both a war with Atlantis on the horizon and some sort of Vampire Civil War that Jason Aaron is trying to set up.
I empathize a bit with the rock and the hard place Steve is stuck in here. He is at odds with the American government. When Ross complained to Steve that T'Challa was the Avengers chair, which put the Avengers under the purview of Wakanda instead of America, Steve told Ross straight up, I don't work for you and the Avengers do not belong to any one country. And now he's taking a leave of the Avengers to go try and save someone they see as a foe, someone they are prepared to go to war with. Should Steve fail in any of this, he'll have zero recourse after it, he would have burned all his bridges. And still he's doing it. That's a pretty big declaration of love for Namor. He showed this same single-mindedness when saving Bucky during Brubaker's run, if we all recall. It's who Steve is, maybe he's not the most expressive of guys but his actions speak for him.
...Also, it was Steve, during Robinson's All New Invaders run, that organized and planned Namor's rescue from the Kree, recruiting Jim and Bucky into it.