I was always under the impression that Satanism did not recognize the concept of “morality” as a legitimate principle with which to be concerned with (aside from considering other people’s flaw perceptions about it, of course).

I think you'll find that first impression is not really adequate to the reality of Satanism.

Satanism criticizes received views about right and wrong. But its criticism is, in part, an ethical one: received views about right and wrong are wrong, because they promote irresponsibility or hypocrisy.

Responsibility and the rejection of hypocrisy are regarded as moral bedrock.

Sometimes upholding your responsibility or avoiding hypocrisy is dangerous, hard, ignoble, inconvenient, or unlikely to succeed, or even doomed to fail. Sometimes there's no particular pleasure or advantage in it.

But you still do them because to ignore them would be irresponsible or hypocritical.