Whilst I understand the sentiment regarding selfishness, I'm with Filthy Monkey on this one - it's a benefit available to GGLs.
One could also say that it's selfish to book several revenue tickets the same day, flexible or not, intending to use only one and cancel (or not) the others. The only difference is scarcity of available seats but some people could be just as inconvenienced by that, for example if the "multi-ticket booker" has taken the last seat available on booking fare D, the next person getting C or the cabin even being zeroed out. There are many legitimate reasons to book several flights the same day intending to fly only one and what way they are booked (paid, miles, low-cost, full fare, etc). and whether or not they are refundable are really only the concern of the person making those bookings and I'm really not sure they can really work out how it will impact others plans. It's part of the reason airlines overbook flights. If your plans firm up then it would make sense (if refund is due) and be fair to cancel at that point or let the airline know which flights you will not be taking.

Not to my knowledge. I have booked and ticketed two flights the same day on AA intending to take just one. If they are ticketed and paid for then I can't imagine the system will cancel one. If they are not ticketed it's a very different story and the last one booked will usually be cancelled.