I still do not understand why so many people don't see the obvious.
Many people don't care, they're cheap enough that they're fun. To me, and a lot of other folks it's just a pure giggle to run these things.
I used to spend money upgrading PCs and wasting electricity on the old distributed computing projects like RC5, OGR and SETI@Home. Those made nothing back, it was just a race on a web page.
Now I spend money of mining widgets, but at least they make a bit of money back so I can buy more mining widgets.
Its not surprising there are people like you (mining for fun, not profit), especially with these USB devices. What is surprising is that are so many that they are driving the price, even from machines that are way beyond funny prices. You'd expect for profit miners not to buy when its not profitable and hence, despite some "for fun miners", you'd expect the price to drop to somewhere around marginal profitability but thats not happening.