Using a packet interceptor program isn't hacking. Who said you need it? I said so because it is an easier way. It doesn't affect the game in any way.
"A hacker is one who enjoys the intellectual challenge of creatively overcoming and circumventing limitations of programming systems and who tries to extend their capabilities The act of engaging in activities (such as programming or other media) in a spirit of playfulness and exploration is termed hacking."
-Wikipedia
A packet is basically a code that has been sent. They are not big enough for something major. They are written in hex and are used to modify (legit or non-legit) something (here, a game). I don't really consider WPE PRO as hacking, it is just an easy to use tool (which I rarely use). It IS considered as small code if you start as a plain packet.