The closest I saw was in Souter's opinion for the unanimous court,in that he comments on Chester Darling's argument that because the parade organizers had excluded the Klan and an anti-school-busing group, they were equal opportunity neutral.
The ruling is available, but is pretty vague about judges' views.
From a Globe piece on April 26, 1995:
"My clients are ecumenical -- to a point," Darling answered. He noted that over the years the veterans had kept a few other groups out of the parade, such as the Ku Klux Klan, an antibusing group and antigay demonstrators.
Breyer, formerly on the US Circuit Court of Appeals in Boston, suggested that the "actual reason" for the exclusion of the gay group was "that it makes your clients feel uncomfortable."
But other justices seemed to be concerned about the rights of the veterans.