This seems to suffer from the usual problem of non-astronomers not understanding the breadth of the problem they think they're trying to solve. That is, they've vaguely heard that the problem is in the rotation of disk galaxies, and so they propose solutions that depend on the rotation (and maybe also on the flattening).

But the "dark matter" problem occurs for basically all galaxies, including things like elliptical and dwarf spheroidal galaxies that have no bulk rotation at all. (And also disk galaxies where a significant fraction of the stars and gas are counter-rotating.) The same applies to groups and clusters of galaxies.