So, was I guilty of plagiarism?

Artwork by Tarek Chemaly or by someone else whose work I have "borrowed"

"If we're looking for originality, we might as well go home." John Hegarty - when he was president of the jury in Cannes Lions. On the surface of it, this remark from none other than advertising great John Hagerty is dangerous, it basically allows us all to take each other's work and appropriate it as our own and get away scot-free.
Themes used creatively in advertising are basically the same - families, outings, good times, motherhood, graduations, slices of life, and the list continues. So with this in mind, all ads should look the same and truth be told most of them do. Actually, when a student is confused as to how to do a proper layout for an ad, our common advice is "look at any magazine, if the ad is good enough for L'Oreal (or insert the name of any multinational here) then it is good enough for you in terms of layout".
"What has been will be again, what has been done will be done again; there is nothing new under the sun." (Ecclesiastes 1:9) and Arabic poet Ka'ab Bin Zouhair did say "I only see what we say but regurgitation, or a repetition of something we already said" (the artwork above). These quotes seems like a laissez-faire invite to basically go out and pick whatever we want from other people's work. Which perhaps we actually do.
Besides as someone asked me in a recent discussion "what's in it for you?" - true, what's in it for me? Let my students go and get "inspired" or "borrow" their projects - what's in it for me if they do. Let my clients show me ads previously done and tell me "I want an ad just like this" (yes, it happened with a former client), let my clients say "I asked my lawyer, the penalty for copyright breach is much lower than the charge of using the work in question, so I will use it" (again, it happened with a former client).
Again, what's in it for me?
John Hagerty is too smart to fall into such a trap, he was simply saying, that since everything has been used and over-used, it is how we dress up old ideas into new ways and dip them into innovative sauces that matters.
The idea of "girl dancing in a perfume ad" is a silly, uninspired one. Then you have Spike Jonze for Kenzo.
1984 by George Orwell? Sure. Then you have Ridley Scott for Apple.
Two major stars divorcing? Yellow press material. Then you have Norwegian Airlines.
"Watching our channel makes you love movies". Dull, boring, unimaginative. Then you have "The Bear" for Canal+.
"Good artists borrow, great artists steal." The quote is attributed to a certain Spanish painter.
In this context, calling someone a "thief" could be a compliment.
But hey - I chose this shocking title for this post maybe to stir a debate.. The reason?
Yesterday, Souk Sawda (an instagram account that sells vintage material) asked to "delete immediately" two of my artworks because "the image is ours and we can prove it" adding that I should not "edit [our] images" and claim it as mine. I replied saying that according to copyright laws, I was in the clear. Yes, I screenshot the images for the Souk Sawda account, and gave them a very complicated conceptual/artistic treatment. The images were modified enough, were artistically treated, they were of uncertain origin - these were international images which were appropriated by a Lebanese erotic magazine published in the 60s and no one can clearly claim ownership of them, in addition my instagram account is mostly an educational one - meaning certain copyright rules do not apply. Last but not least, Souk Sawda and myself are not in the same business and I do not sell competing goods (or counterfeit, plagiarized ones based on theirs).
I did delete the images out of courtesy, even I knew that ethically and legally I was in the clear, but I wanted to initiate this debate about the notion of plagiarism simply because I hold ideas sacred and dear.