I visit animal shelter fairly often
There's a really nice no-kill shelter by my house that I volunteer at on Wednesdays! They help a lot of people adopt pets.
I see. Is a no kill shelter different from regular animal shelter
Yes, a "no-kill" shelter is an animal shelter that does not kill healthy or treatable animals even when the shelter is full, reserving euthanasia for terminally ill animals or those considered dangerous to public safety. A "Kill Shelter"... well you can guess.
I see, then i guess the one i visit is a kill shelter. Now i am feeling bad about it
Well, the shelter you visit might still perform valuable services. Most humane societies, animal shelters and rescue groups urge animal caregivers to have their animals spayed or neutered to prevent the births of unwanted and accidental litters. If they spay and neuter there they might be keeping more unwanted animals from being euthanized!
Ok i see. Neutering animal is a form of castration right? 
Sort of, the male-specific term is castration. Neutering can happen to females or males!
Okay. But don't you think this is wickedness on the animal part too. 
I don't know that I'm comfortable assigning morality judgements to the behaviors of animals.  All biological entities seem to desire to reproduce, should we call this desire wicked in a domestic dog?