Unless you have a very heavy (or light) foot on the brake pedal, you should have no noise.
All cars in this country (if I remember correctly) have not had asbestos in the brake pad material since the eighties. So don't know why anyone bothered talking about the substitute materials used now. I would say the vast majority of brake pad material is the same regardless of what car you drive (ceramic brakes excluded) so squeaking can be caused by a couple of things;
If you have new pads fitted (eg; when you have a new car or after replacement) then having too light a foot on the brake pedal therefore braking over a longer distance before stopping but, braking very gently, can lead to a glazing of the brake pad surface causing the surface to be harder and squeal. The way to sort this out has been to have the pads removed and roughened up and driven 'normally' again.
On the other hand, braking too hard when the brake pads are new can have the same effect. As far as I have been told by the 'fitters' of brake pads, you should drive your car normally without undue force on the brakes for a couple of hundred miles to allow the brakes to 'bed-in'. I have always done this with whatever car I have had and every time I have brake pads replaced and have never had squealing brakes other than at times when the brake wear indicator has sounded (mentioned in another post) and new brake pads got rid of the sound OR when I have had a stone chip stuck in the brake pads scraping against the disc. This is easily cured either by simply putting the car into reverse gear and backing up a bit to try to dislodge the stone or removing the offending brake pads and allowing the stone to drop out.
If your dealers mechanics cannot cure the problem then if I were you I would advize your dealer that you will take the car to an independent mechanic to verify if there is a problem or not and make the dealer aware that if there is a fault found then you will expect all costs to be met by the dealer for rectifying the problem.
Hows that? Too aggressive? I don't think so. You are entitled to have a nice comfortable car to drive that is hassle free. You should have the same experience with your dealer.