There must always be an ongoing review of standards relating to fitness to serve.  We need the best and brightest to protect the interests of our nation, and where certain characteristics might affect performance, at the very least, allowing active service should be delayed until the answers are certain.
However, I think the questions about transgender individuals have nothing to do with their being transgender.  The question should be can they carry and shoot a gun, and perform the tasks assigned.
Better topics of review would be:  "Should a narcissist be allowed to be President?"  "Should a liar be allowed to be President?"  "Should someone who lies on an SF86 form be allowed to work in the Whitehouse?"  "Should someone using a Federal position to pursue personal  private business interests be allowed to work in the Federal Government?"  etc.