Concert tickets why are resale sites allowed?

[irocfan]

just curious here every time a popular group releases tickets they seem to be all snapped up a nano second after the lines open yet there are loads available on the resale sites (stubhub/viagogo/whatever) at vastly inflated prices.

I thought that touting had been outlawed so how is this any different? Surely it's not beyond wit or reason to ban any ticket sales except via the band's website or the venue. You can't go? Simple sell it back to the venue.

While I'm having a moan WTF are the extra fees that (for example) the O2 add on to their tickets as processing fees? Seriously if I have to pay it then it's part of the ticket price not a separate charge.