We saw how the general public and the mutant community reacted to M-day, so what would be the point ?
Some freaked out,some cheered, some saw that as an opportunity => if Doom involvement was known, some would freak out, some would cheer him up, some would try to use him.
He's not blind to the plight of mutants, but X-writers will never allow anyone but the X-Men to try and tackle mutant issues.
Otherwise, they'd look incompetent, plus, it allows their martyrdom complex to have a leg to stand on.
50 years of stories and they are still treading water...That's deliberate.