Nah, its common sense. No need to maim an animal for no logical reason. Neutering helps reduce stray cat popuations/unwanted kittens.
Declawing a cat only serves a purely cosmetic aspect for the owner. It does not help the cat, it does not reduce stray cat populations it does not help to prevent the spread of cat aids.
No point discussing it further with you. You have your position and won't budge despite being shown valid reasons why its wrong to declaw cats.
Last point :
Feral cats live on all continents except for Antarctica. The worldwide feral cat population is estimated to be at least 100 million. The United States' feral cat population is estimated at 60 million, Australia's at 12 million, and Britain's at one million.
from Wikipedia, not the best source but cba to go looking around more. Neutering really plays a huge role in reducing stray cat numbers.