Something of a facile distinction, given that the construction "objectify women" has a strong negative valence, and implies you're doing something wrong. I won't say "immoral," since the modern moral majority doesn't use that term. It marginalizes the voices of those with woman-aligned identities, I guess.
You can say the point of Hustler is to objectify women, or you can say the point of Hustler is to let people get their rocks off. These are both true, as far as they go, but there are assumptions in each statement that you need to unpack a little. "Getting your rocks off" acknowledges and tacitly approves of a certain framing of the magazine. "Objectifying women" acknowledges a different framing and includes a tacit disapproval. To say that a criticism of the magazine as objectifying women is reasonable because it is true is weak, because you're not acknowledging the framing. The rocks-off framing is equally true, and in the same way, but you might still disagree with it because of the framing.
Hustler is a magazine that pays women for provocative pictures, and it packages and publishes them for the sexual gratification of men. I think it's fair to say that it objectifies women, in the sense that the men looking at the pictures are treating them as objects of sexual gratification. To say, sans other context or sentiment, that the magazine objectifies women, does, however, suggest a puritanical goal or objective. Out of a large bag of potential framings, or combination of framings—libertarian, sex-positive, live-and-let-live, religious, enlightenmentarian, humorous remove, indifference—you're selecting the framing that suggests you want this thing to be attached to a strong negative valence. It's also done in the epistemically cowardly way in which many social criticisms are now made. If you said it was immoral, that would at least tip your hand a bit, and show a little conviction.
OP's criticism was quite civil and reasonable compared to some anti-pornography people I've seen before.
And it's absolutely true magazines like Hustler objectified women! Have you ever seen one? The entire point is to objectify women and sex!
That's entirely different than claiming you're evil or bad for producing porn...