How many human lives and human energy went into Notre Dame? How many lives would its continued existence inspire? Humans are far more temporary than art and culture. Art and culture connects us to the people that came before us.
It's a pretty personal question. I admire the archaeologist you described, but I believe no one should feel obligated to do the same thing.
How much risk would you be willing to take to save the artworks of Notre Dame?
If there's even a small but significant risk to one's life then nobody should feel obligated to do it.
I think that's the best explanation I've ever heard for why art and culture are so important.
PS: I had no idea it was so controversial to forgive people for not risking their lives for an inanimate object.
If your argument is that we shouldn't criticize people for choosing not risk their for inanimate objects, can you point to such criticism in this thread? I haven't seen any.
Some people will categorically shy away from any perceived risk to their own safety, even if the estimated chance of saving a valuable object is very high. At the other extreme, some people would endure suffering and death to save what they recognize as priceless artifacts of history and culture.