Are the brake pads toe'd?

Define "aligned fine"?

Squeal on rim brakes is almost always due to dirty and incorrectly toed pads. Ensure they are clean and that the leading edge of the pads makes contact with the rim before the rest of the pad.

What he said. This OTOH:

>>>So annoying... I'm embarrassed to stop :)

Don't worry about it. I assure you no one around you will notice, or if they do they won't care.

I just fixed (a/k/a vastly improved but not eliminated) my new carbon rim squeal and bad brake performance by doing a very focused and precise brake set up. Tiny changes made a huge difference.

I set the toe using the business card trick and there was a major difference in performance and squeal just between a folded business card and an unfolded card. I even got out my feeler gauges to make sure the brakes were centered to a ridiculous tolerance. I still get some squeal under super hard braking but now 98% of the time they are quiet.

What's the business card trick??

I had squealing on my carbon wheels and was told by the manufacturer to clean the carbon brake track with alcohol, then make sure to "toe" the pads (so the front corner touches the brake track before the rest of the pad does).
I did these things and no longer had any kind of squeaking.

Roll them up into cylindrical shapes and jam them in your ears.

Clean your braking surface... hopefully the pads aren't contaminated with whatever could have been on your wheels braking surface. Have to do this on my mountain bike from time to time.

Best idea yet...

I have the same issue with my hed jet blacks on my speed concept. Went back to the bike shop 3 times to get the brakes adjusted. I'm using new jagwire pads front and back. Finally got the squeal out of the front brakes with massive toeing in, but still remains in the back brake. I'm not sure what else to do except to wait it out. Maybe I'll try alcohol on the brake tracks. Any other ideas?

I have never heard of the business card trick, but I assume that you would take a business card and fold it to adjust the brake with the card pinched between the later part of the brake pad and rim to toe the brakes slightly and equally.

Alternatively you could clothes pin the business card to your fork to hide the sound of the squealing brakes.