But maybe its harder to measure MilkyWay than to measure the mass of other galaxies. Still, they cannot directly measure the mass of anything out there. So they are implying the mass by looking at the light coming from them and from neighboring objects. I would rather look forward to them being proven wrong about their assumptions because we would learn more. Maybe they might learn something that could help us out here on Earth.
So I prefer to look at theories which challenge the accepted science in the hopes that new discoveries might spark new technologies here at home.