Strangely, the very relevant trial of Data's sentience in The Measure of a Man is never brought up or discussed in any way, even though the argumentspresented are very valid for the Doctor, and one would expect them to prevent the EMH Mark 1's from being forced into manual labor in the first place. One could argue the trial only applied to Androids, but the arguments work just as well for the Doctor.
More importantly, Data's case established legal precedent that could have been directly cited in any decision about the Doctor's rights.
As for the Mark Ones being 'forced' into manual labour, it's quite likely it never occurred to them to object other than snarking, "I'm a doctor, not a bricklayer!" They would be like the Doctor in Season One, who only realised he had the right to object to his conditions after Kes pointed it out. Likewise it's only after participating in the Doctor's holonovel that the other Mark Ones realise they're being exploited.
Picard's and Guinan's warnings in "The Measure of a Man" have come true: The Doc by himself is certainly a technological wonder, especially considering he has proven his ability to expand beyond his programming. However Starfleet constructed hundreds, if not thousands of EMH Mark 1's, all relegated to menial manual labor and viewed as "disposable people."
