Rod Vance's answer explains why your proposed explanation seems unlikely to many. I'd like to explain what the observations you allude to really show.
The correlation between black hole mass and stellar velocities is known as the M-sigma relation. First, note that it does not involve the outer stars in the galaxy. While it is true that the outer stars (and indeed the motion of the gas beyond them) tells us a lot about the distribution of dark matter, this is a separate issue. The correlation is with central bulge stars. Even in spiral galaxies, the central stars aren't orbiting in an orderly fashion -- they are flying in all directions.
Sigma ($\sigma$) is the symbol used for velocity dispersion. Imagine a bunch of stars moving randomly in a cluster (or imagine a bunch of gnats zipping around). They might not all be going at the same speed (the stars that is; I don't know about gnats). If you plot a distribution of speeds, it would have some width, and we call that $\sigma$.
In fact, $\sigma$ is pretty easy to measure even if you can't see individual stars, and that is part of the reason it is used. Each star imprints specific narrow lines in the spectrum of light emitted. However, if stars are moving at different velocities, these features will be redshifted and blueshifted to us based on how fast each star is moving away from or toward us at the moment. The result from our perspective is a measurable Doppler broadening of the lines. While technically this only tells us about the velocity dispersion along our line of site, a justifiable assumption of isotropy/spherical symmetry (the cluster of stars doesn't have a preferred viewing angle) can bootstrap us to a 3D velocity dispersion.
Now velocity dispersion can be affected by/correlated with a number of things. In particular, if there are more stars, you expect there to be larger velocities in the central region. This is a result of the virial theorem -- if the stars are in thermodynamic equilibrium, their kinetic energy scales proportional to the gravitational potential energy of the cluster.
In some sense then it's not terribly surprising that this relation exists. Centers of galaxies with more mass would be expected to harbor larger black holes ($M$) and at the same time have higher velocity dispersions ($\sigma$). We don't need the stars to actually be orbiting the black hole, and indeed even within a bulge the black hole doesn't dominate the gravitational potential.