a website with ethical reasoning

I searched a website which shows ethical reasoning about animal fur.
This site says that we should not deprive the animal's right.
If we see this site, we can understand killing animals are ethically and morally wrong.

http://www.bbc.co.uk/ethics/animals/rights/introduction.shtml

Please read this sentence in the site.
"Animal rights supporters believe that it is morally wrong to use or exploit animals in any way and that human beings should not do so."

"morally wrong"
There is no practical reason why it is wrong, and this is moral claim.
From these words, we can know that killing animals is bad is a social norm.

"human being should not do so"
 These words reccomend us not to use or exploit animals because it is not  right thing to do.
Animal lovers blieve that human should not kill animals blindly and originally.
However, we can't understand why it is not right.

Maybe animal lovers can't explain why killing animals is wrong logically and they can't persuade us
because this is ethically wrong.