I don't interpret "oh you're a real person" as saying "oh wow, you're more than a sex object". I think the reaction is more in line with the awe of meeting the flesh and blood subject behind a static photograph (and an alluring photograph at that).
You make it sound like this was 500 years ago! Anyway, no one is saying to retroactively condemn the people who did it. They are saying to stop using it now. The context is the use of the picture in the here and now contributing to non-inclusion of women in tech.
If Lena came out saying she felt abused by the distribution of her photograph in this manner and that the practice needed to cease, I would agree with you. But her comments indicate to me that individuals ought to reconsider their reaction in light of the subject's perspective. If we respect what Lena believes, and sought her out to document her opinion, then we should seriously consider the weight of her opinion of her own life and own image versus ours.
Who are you to say anything about their character or quality as “objects”? It seems uncharacteristically harsh to just make an assumption like that.