Some people say so.
Carrageenan is a natural substance extracted from red edible seaweeds. It is widely used in the food industry as a thickener, emulsifier and stabilizer. The main applications are for dairy and meat products. But you may also find it in toothpastes, face creams and some over-the-counter medicines.
I checked my frig. Yes indeed, I have carrageenan: Breyer's ice cream, Foremost blueberry yoghurt, Dairyland 2% cottage cheese, No Name 2% canned milk, President's Choice blueberry cheesecake, and M&M Spinach, Artichoke and Cheese Dip. The one I didn't expect was Dempster's Tortillas.
Apparently carrageenan is present in many dairy substitute foods such as almond milk, soy milk etc.
The following are links to a few of the online articles related to carrageenan:
Notwithstanding the guru's of online health websites, my concern with carrageenan stems mainly from my wife's experiences. She inevitably gets gastro-intestinal distress from eating ice cream. I generally offer to sacrifice myself and eat all of the Breyer's myself. However,so far she has declined these kind offers.