Okay, I'll go on record as being the first person supporting the current sitout policies.
I think that if a player pays the buy-in for the tournament, s/he is entitled to play that tournament however s/he wants. If the player wants to sitout the whole time and try to make it to the money, that is no different than folding every hand, which is a perfectly acceptable strategy (though not necessarily a good one.)
Keep in mind that as the person sits out, s/he also misses out on the opportunity to play great hands like AA, AK, KK, which could advance the player's chip count.
One possible way for a player to abuse this ability is to buy in to multiple tournaments at once and sit out in all of them, hoping to land in the money in some of them. The way
PokerStars handles this is by limiting the number of tables one can sit out at any one time, so that sitting out is not profitable.
Yes, I agree that sitters are annoying. I played a game the other day where a person went all-in early, won a big pot, and sat out the rest of the game to finish in the money. In the end, I was racing him on the bubble, but couldn't catch the right cards and wound up finishing just out of the money. Unfortunately, that's the breaks. Whether I like it or not, his strategy is no different from what would happen if he folded every hand after the big win or lost his connection, so that makes it a valid strategy.