There are many reasons why, as a decent human, that we shouldn't use sarcasm.

Fortunately for me, conforming to how you think I should behave is not high on my list of priorities. IMHO, one can still enjoy sarcasm and be a very decent human being.

According to Oscar Wilde “Sarcasm is the lowest form of wit, but the highest form of intelligence.” So I may not be very witty but I am very intelligent - maybe more intelligent than you are VBG. And if you disagree with Oscar Wilde you are probably a bigoted homophobe since he was gay...