Well, I'm going to be the contrary person by the looks of things.
Poaching/headhunting is awesome and I strongly think it's a good idea and a very important part of EVE.
Every player that isn't in nubcorp is potentially working against you, or at least not for you. The goal of EVE is to get a leg-up over people working against you and/or be better than those not working for you. Several corps/alliances have done this to great success, pulling numbers from their opponents (and other 'neutral' corps) to fill their rosters.
As for headhunting, most people want their corp to succeed. That means having the best, which means finding and convincing the best pilots to join their ranks. If their current corp can't provide the same benefits that your corp can/does... why not try to convince them to join your cause? Also, corp benefits aren't everything; I went from a corp that provided full replacement of any and all T1 hulls, and a heavy subsidy for T2 hulls (while we were making a few bil/week drinking beer), to a corp that had a T1 frigate replacement program and income in the corp was very limited and took much more effort.
The important thing to note about poaching... they may pull someone that's actually loyal to the corp being poached from. That means they have a mole that was actively recruited.