Generally he does this (or plays math/word/science games). And if he doesn’t, strangely our internet connection gets slow on his devices. Shucks, I guess it’s time to read a book.

No one disputes that.

The reason why people consider it harmful is that frequent watching, which is the platform's #1 priority, creates addiction.

TV is absorbing, as a child with 3/4 channels there was often a time when the was nothing of interest and that helps one week interest elsewhere (aka boredom). If there's no point at which there's nothing interesting to watch it's easy to sit and absorb stimuli out of habit.

Maybe addiction can develop, does develop? If you do an action habitually you're still doing the same physically as perhaps you would as an addict.