We have many, what I term, "bath-tubber" car care companies in the States.
Many just find a common formula in the "book" and decide to "up the agressive components" in order to make the product work faster, as that is what their customers request. Of course the "customers" are not aware of what various components may negatively affect in the long term many of the surfaces they are used on.
Over here, xylene is one of the chemical additions, even though California, OSHA, etc have recognized it's carcenigenic values and require very strong warnings on the product label.
Most do not even take the time to "read and follow" the label's warnings.
The common response is "It works great for me and I have never had any problems, etc".
A little time spent doing some research regarding solvents such as xylene on the human body might wake them up.
I always have a quart or so of xylene in my fire proof solvent cabinet and won't even open the can without wearing chemical proof gloves and if going to work with more than a half an ounce, wear my good respirator.
Can be very nasty stuff! As many clorinated, etc solvents can be.