Well, Steve Ditko wasn't a Libertarian, he was an Objectivist.
While the two belief systems overlap, the Objectivists and Rand herself always despised Libertarians as "right-wing hippies", while Libertarians typically knocked Rand off while treating all the non-economic parts of her belief system as the bullshit they were.
If we're going to differentiate between Trots, Orthodox Marxists, Marxist-Syndicalists, and Industrial Unionists (which we should), it seems fair to be aware of right-wing ideologies' splinters, especially when they are as different as a fully-formed philosophical system for assholes vs. the much broader but more politically-economically-centered church of US Libertarianism.
I think it's understandable to ask "why does this matter? they're both hyper-capitalist belief systems", but I do think if one wants to know her enemy, one should be aware of her enemy's divisions.
Well, that and because Libertarianism produced the
Left-Rothbardians, who managed to be surprisingly anti-corporate and weirdly a little socialistic in ways that at least marked them as better than Objectivists.
I want to be clear that I'm not endorsing people like Konkin, who was in that circle but who also promoted Holocaust denial, nor am I endorsing the many, many, many Libertarians who have turned out to be jackasses, Social Darwinists, elitists, pedophiles, racists, homophobes, transphobes, misogynists, anti-Feminists, Gamergaters...
You get my point. That said, Ditko definitely didn't seem like some of the really awful examples of Objectivists, at least.