those petitions won't do a thing. those are companies, they release whatever they think will turn a profit, and they have huge back catalogues that they are slowly churning out.
deat rides a horse has already been released anyways.
plus, MGM doesn't even own the rights to most of these movies outside Europe (and in Europe only outside Italy), so they won't ever be able to release those in the US anyways, such as the mercenary and death rides a horse.
just wait... they'll come some day