It should be noted that Kagan didn't bar military recruiters from Harvard. When she became Dean of Harvard's Law School, she continued the policy of her predecessor. Under Harvard's policy, employers whose anti-discrimination policy did not comply with Harvard's anti-discrimination policy, which the military's did not because of it's anti-gay prejudice, were not allowed to recruit using the university's career center infrastructure.
However, military recruiters *were* allowed to recruit through student organizations, which could secure space at university events for military recruiters. During the period between the time Harvard adopted this policy, and the time at which the Supreme Court struck down Harvard's policy, military recruiters continued to actively recruit on the Harvard campus and at the law school, only through the auspices of a student organization, not the University career center.
Kagan did not create this policy, she merely followed it as Dean of the Law School. When the policy was struck down by the Court, she complied with the ruling and allowed recruiters to operate through the career center.
Truly, this is scandalous.