I think it also depends on how ppl understand the concept of the word "satanism". I am an atheist and used to live in a asia country, we don't use any word like satan like you said "to define as the source of sorrow..." And I don't think we even have that word in native language. We have something else comparable to that but still what I want to say is that Satanism may sound bad to you but for others ppl It's not.

To ppl who doesn't have any prejudice against Satanism, the Satanic temple does indeed provide good causes, especially even more now given how bad others religions are (I don't want to name them but I am sure we know who)