Questionable conclusion about wide lines

A paper, www.arxiv.org/abs/astro-ph/0511010 , titled "A Super Star
Cluster in the Outskirts of a Galaxy Merger" claims that a stellar
SDSS object is a super star cluster at the distance of the nearby (3
arcmin) galaxy NGC3310 because of its 1033km/sec recession speed and
wide absorption lines. The paper compares this scenario with the
alternative that this is just a high-velocity Galactic star, and says:

"Therefore, SDSS1039+53 could be a Galactic high-velocity star, like
that recently discovered by Brown et al. (2005). Several methods were
used to derive the stellar parameters under this assumption. ...
The spectrum and colors are consistent with classification of
SDSS1039+53 as a horizontal-branch star at 60 kpc. However, the line
widths for Ho and Hd are much larger than that of H.. Finally,
the abundance obtained using the Beers et al. (1999) calibration of
the CaII K line and the colors is [Fe/H] = -1.88. Taken as a whole,
these results suggest that the spectrum of this object is composite,
which might be expected if it is not a single star, but the integrated
light from a cluster of stars."

The article also states that the object is an unresolved point source.
It seems to me that the Ho and Hd line widths could equally well be
produced by a rapidly rotating star. Is it not likely that a Galactic
high-velocity star could be rapidly-rotating as well, since some
high-energy event was applied to it to give it the velocity? Why is
there a need for an extragalactic "super star cluster" scenario,
especially as this object looks entirely star-like.

Eric