For some reason, the "gays in the military" issue seems to come up only in presidential elections. However, the law that keeps gays out of the military comes from Congress, not the President or the military itself. The law is stated in U.S. Code, Title 10, Section 654 .
That law explicitly states that Congress has exclusive power to make such rules:
"Section 8 of article I of the Constitution of the United States commits exclusively to
the Congress the powers to raise and support armies, provide and maintain a Navy,
and make rules for the government and regulation of the land and naval forces."
If you wonder why Congress would make such a law, Section 654 gives plenty of reasons,
summed up as follows:
"The presence in the armed forces of persons who demonstrate a propensity or intent to
engage in homosexual acts would create an unacceptable risk to the high standards of morale, good order
and discipline, and unit cohesion that are the essence of military capability."
Retired Brigadier General Keith Kerr, being a Democrat, should be asking his questions of
the Democrat-controlled Congress, not Republicans running for President.