Can someone tell me how a flag, in violation 'Title 4 USC 8: Respect for flag', is or was allowed on a Military Post?

Since we can't see it, I can't respond.

Thank the supreme court...Criminal penalties for certain acts of desecration to the flag were contained in Title 18 of the United States Code prior to 1989. The Supreme Court decision in Texas v. Johnson; June 21, 1989, held the statute unconstitutional. This statute was amended when the Flag Protection Act of 1989 (Oct. 28, 1989) imposed a fine and/or up to I year in prison for knowingly mutilating, defacing, physically defiling, maintaining on the floor or trampling upon any flag of the United States. The Flag Protection Act of 1989 was struck down by the Supreme Court decision, United States vs. Eichman, decided on June 11, 1990.