Last time, Mexico barely edged the US out in rankings and got seeded as a result, instead of us being seeded. By the way, Mexico did participate in the Confed Cup, and I remember some on some soccer boards doing calculations of how it would have been different had the US won the Gold Cup and went to the Confed Cup. Well, that's past history, but it was very close with Mexico edging the US out.
Now, of course you can get minus points, but the question is NOT whether it's better to have sent the A team to BOTH the Gold Cup and Copa America - obviously, that's the best option! I as coach would have done that.
No, the question is IF you had to choose: either send the A team to Copa or the A team to the Gold Cup AND participate in both, well the US definitely did the right thing.
And winning the Gold Cup gets you more points by far than losing all three games in the group stage in Copa America. So, we already easily got net points there, even without the Confed Cup.
As far as the respect thing, being fair, arguments on both sides have merit. It's hard to argue the Europeans (even many average soccer fans) lower their estimate of US ability if one JUST goes by record. I've been in such debates before and did a bunch of statistical stuff, but the key point is it seems that if you don't know it was the US that had that particular record, the estimate of ability seems to be higher. I mean I've heard so many arguments putting Mexico well above the US, teams like Turkey or Sweden, etc.. all teams that are realistically in the same class as the US simply above us. And that's evidence of SOME sort of bias, not sure what.
On the other hand, the US is asking for more respect than it deserves, that's clear. I mean in the last 4 WC we came in last, close-to last, made it to the second round, and went to the quarter-finals. That's not that great a showing. So, I think it goes both ways. And sending such a weak team to such an important competition as Copa America is disrespectful, not to mention a waste of a great chance at getting the kind of experience the US needs.