In making the EMH the best character on the show, it was only a matter of time before they really just nailed down whether he should be given as many rights as, say, Data had.
There was an “out” with Data – no one knew, precisely, just how he was built. No such out for the EMH and, as such, the whole issue of Holographic rights is rather thorny. If Robert Picardo weren’t so good it would all hardly matter.
Anyhow, Starfleet is smart enough to hedge their bet a bit. Whether he is sentient or not remains to be seen, but he is an “artist.”