in so many cases, after all, the artist was there

Does "in so many cases, after all, the artist was there" mean " in so many cases, after all, artists attended the battle fields and eyewitnessed them"?

Context:

How truthful is war art then? Is it fiction? Does this matter? Many works reconstruct events that the artist saw and experienced but rendered later. Photographs, official reports, and war diaries may assist this reconstitutive process, but the desire to paint a good picture may compromise its veracity. We expect war art to be truthful – in so many cases, after all, the artist was there– and it is sometimes hard to accept that a piece may be not an eyewitness account as much as a synthesis of things seen, remembered, and read about.