The metals and plastics used in their manufacture is pretty minimal compared to cars or home appliances.
Their power consumption is low compared to heating or lighting (a macbook consumes power equivalent to about two lightbulbs, and most devices use less).
Earth metals represent probably the biggest environmental impact of consumer electronics. They're not actually rare, just expensive to mine, so there isn't an issue of sustainability. (As in, the earth metals aren't going to run out any time soon. There's some nasty environmental damage in the vicinity of the mines, but that's limited to a particular area).
I'm trying to fathom the reasoning behind this comment. Is it that because electronics are really useful and beneficial, they must have a proportional cost?