Dominus is saying that if you watch sports the right way, it can well be a worthwhile experience. You are saying that most people just zonk out in front of the set.

You are both right.

For the record, here is a data-point. At one point I found tennis uninteresting to watch. A few years later I saw tennis on TV (this was a couple of years ago, I had a TV) and I found it a fascinating game to watch. But I was still bored by watching basketball.

What changed?

Well I had started playing ping-pong fairly often with friends. Tennis and ping-pong are closely related sports with similar factors mattering. Obviously they are very different sports, but my interest in playing ping-pong meant that I was suddenly looking at a different - and far more interesting - game.

Likewise until I tried to program, I found discussions of the practicality of programming boring. I could give detailed considerations of whether a set being uncountable meant that it was in some sense larger than a countable set, or merely that it had a more complex internal structure. (The orthodoxy is larger. I am not entirely orthodox in my opinions about the foundations of mathematics...) Today I find it more interesting to read discussion about questions like whether a better mental model for programming is black boxes with defined behaviour, or black boxes with fixed inputs and outputs you wire together in a network. (Check out the link on my home page about flow-based programming.)

The topic, from sports to CS to math, is irrelevant. There is a world of difference between observers who are engaged in a learning process and observers who are not. I am, like Dominus, someone who enjoys being in a learning process. This engagement has no causal relationship with the subject at hand. Indeed I am not even sure that there is even a positive correlation between that kind of engagement and the subject of their engagement.

But there is a strong correlation between having that kind of engagement and becoming competent.