Having mining equipment lets me speculate on many different coins. Naturally when I bought the equipment I was (and still am) gambling on making enough profit simply by mining, to profit over the cost of the equipment, in addition to any profit from price increases.
Only in the same sense that having dollars that can be used to buy bitcoin on an exchange which is then exchanged for many different coins lets you speculate on many different coins.
I don't think that anybody is bashing mining here. The point is to drive home the principle of whether or not the initial investment capital could have yielded more wealth by simply
buying coins.
Scrypt mining doesn't give any more flexibility to get moar coinz than does buying them with bitcoin. It might be enjoyable, it might be a good way to learn more about building a PC, etc. But it doesn't
necessarily afford any benefits over buying coins. Especially since GPUs suck a lot of electricity, which also has to be factored into opportunity cost. Even the electricity used by ASIC gear is not negligible in the calculation.