The (socialist) argument is that virtual queues make for a tiered experience where people with more money have quicker access to the rides. In a world that lacks competitive drive (be better in life = make more money = buy the virtual queue) it is easier to complain about what you dont have then strive to earn more. It's why the Eurozone continues to collapse, Japan has a 200% debt to GDB ratio, and the US has to print $85B a month to keep the market propped up. / rant
The reality is they are a great source of income for the parks (systems like Universal Express and SeaWorld Quick Queue have limited if any expense), and help drive up profitiability.
Some parks mismanage their lines, which is what leads to an unpleasant experience for guests who do not pay for the virtual queue.
I tend to avoid parks on days where a virtual queue is needed. I have only payed for one once, and that was at Over Georgia on a Memorial Day weekend. It was worth it. I will be enticed by offers like, "stay out our hotel and get a free Quick Queue". That added value makes me more willing to book a pricier hotel.