I have no view on whether brown or white eggs are better, but the outrage over this story, especially from some professed free marketeers, is bizarre.
If Sainsbury's wants to change the type of own-brand eggs they sell, because they believe consumers favour greener, more animal welfare-friendly products, then that's their decision. They are under no obligation as a supermarket to stock every kind of egg.
Consumers who dislike white eggs can either buy brown eggs from a different shop (thanks to the free market), or indeed buy the branded brown eggs that Sainsbury's will continue to sell.
Maybe Sainsbury's decision will be unpopular with their customers, and they will be forced to switch back to selling brown eggs to maintain market share. Maybe customers will be fine with white eggs, if they taste and cost the same.
Let's leave it to the free market to determine, not anti-woke cultural warriors.