If Kirk Tuck was implying a moral point to be learned by his readers, then he was suggesting a kind of photography censorship.
I think the term "censorship" should be reserved for situations where free expression is suppressed after-the-fact, or prevented from occurring in the first place by someone or some entity in authority. ("In Germany, advertisements for Nazi memorabilia are censored.")
Nor do I think what Kirk Tuck did was "self-censorship," a term I believe typically is used to describe a decision not to engage in free expression because to do so would incur an adverse authoritative response. ("The Chinese student decided not to post the altered photograph of the government official because he feared that to do so would incur the wrath of the police.")
Tuck was describing a voluntary decision he made not to make a photograph. I don't think it should be considered either censorship or self-censorship. You can disagree with his decision, but it was
his decision.
Actually, I'm a bit surprised that the discussion here has focused on that particular incident rather than his more general observations about the nature of street photography, which I thought we were rather interesting.