THE QUESTION IS AT THE END!!
If the gossip circuit is to be believed, Nintendo may be weeding out Pokemon Diamond / Pearl players that are using Action Replay DS codes to beef up their Pokemon. While it may be true that code sniffers may have difficulty in detecting some Action Replay codes, Nintendo managed to sniff out the following:

* National-Dex (After talking with Game Director)
* Catching All 493 Pokemon
* All Shiny

According to floyd of Wii60 forums, using the codes above would block you from getting online.

this is *** i am a 24/7 AR user. the only people i fight against with the AR on is other people who have an AR. when im facing a normal person i leave the AR off. beefing up pokemon, thats *** the only way to beaf up pokemon, that will still even let you online, is with pokerus. pokerus is natural anyway. every now and than a pokemon can get pokerus. so does that make them a hacker. no! plus you can get a hacked pokemon off of the wifi trade center and not even know it. so what happens then, do they get blocked too. sadly yes its ***, this is a worthless attack on people tryin to have fun on wifi.
plus i've heard several rumors that Nintendo is going to try to start charging for wifi another way of stripping an average person of there fun.

now for the question.

Why is Nintendo so ***? Why would they do this?Do you really think they'll
do anything i've just wrote about? and why?

i've just proven every reason of why they want it blocked wrong