The Supreme Court ruled unanimously that colleges must allow military recruiters on campus to recruit (if they want the federal funds, that is).
The court rejected the free speech (free association) challenge.
Until the underlying legal fiction that don't-ask-don't-tell is non-discriminatory or that discriminating against gays in the military is non-discriminatory. Based on that foundation, on what grounds can law schools exclude recruiters when, by definition - by the court's definition the recruiters are not discriminating and thus cannot be violating the schools' policy.
It's easy to tie federal funding to an unconstitutional policy if you simply refuse to recognize it as unconstitutional, right?