I actually don't think it's mean or bad at all. 
If the other people bidding really want the item
they will proxy their maximum bid.  If they lose
they know that they didn't want to pay more for
it.  When you snipe you take a lot of risks
because you don't get a second chance at it. 
There is no way for you to go back and bid again
if you do not bid enough, but as long as you are
satisfied with what you bid you shouldn't be that
upset.  You also take the risk of something
happening to your computer/browser or the auction
could close early.

If I am bidding on ebay I usually end up sniping.
 If I am the first to bid I will proxy, but I
usually never bid first when it comes to cels.  It
is better to wait until the end because there are
usually other people waiting to snipe you.  You
have a better chance sniping at the end then
putting your bid in early and waiting to see if
anyone else bids because by then it is usually too
late for you to bid again.