I hear this opinion on Reddit as well. Yes, it is possible to get "tons of exercise" on your own using body weight, but it is not the same as barbell strength training. You are much more limited because actual strength training is a somewhat scientific process of progressive overload--adding 2-5 pounds per workout to an exercise. You cannot do this easily/precisely with body weight exercises, and additionally there is a reason the barbell is shaped as it is--to maximize the ability to support and balance the weight.

The argument that nobody "needs" gym access is akin to arguing nobody "needs" restaurants--they can all just cook their own food. Or nobody "needs" grocery stores--they can just grow/raise all their own food.