Then your answer is no, we should not be offended. I see the tone, however subtle or mild, and as I mentioned above, as if posturing it as a painting is better because a photograph just cannot do it justice or is not as good.
What exactly do you think he meant buy "Anytime you watch a movie based on a true story, "you have to think of it as a painting not a photograph," Sorkin said."? Why cannot a movie based on a true story be accurately portrayed or thought of as a photograph?
Maybe "offended" is too strong a word, but somehow I feel it's saying paintings are better than photographs.
I don't read anything in there that infers one is better than the other.
A painting is a made up representation of a person.
A photograph is much more a definitive likeness.
Most biographies are not books about the facts of a person's life, although there are definitely facts in there. They are more about why he did this and what was he thinking at such and such a time, and pseudo amateur psychologist/authors sort through his life and say shit like, "well because his mother did this to him when he was 3.... then when he was 30 he did that..." and other such stuff.
"his early bed wetting was the reason he later invaded Russia...."
"he had a mommy complex, so in later years he dressed like her while doing the ironing..."
"he became secretary of state because he had a thing for his dads secretary when he was 9...."
" the screen of the iPhone, iPad, and iPod is black because he suffered through bouts of depression"...
That stuff sounds like a painting, not a photograph.