Yes, there is a difference, but I would still find it hard to argue that a mention of one's sexual orientation is not content of a sexual nature. It says so right on the tin.
By this reasoning, saying I am male is "content of a sexual nature", because that is my sex.
Well, yeah. The expression "content of a sexual nature" really is that vague and opens the door to all sorts of double standards and arbitrarily drawn lines. Only gigantic prudes and corporate lawyers could be satisfied with such broad terms.
The reason your example is a non-issue, however, is that while using it to persecute* on account of declarations of gender requires the kind of drooling mental retardation that seldomly allows one to function in the real world, using it to persecute on account of declarations of sexual orientation requires only common prejudice.
*: if persecution there even was, in the case at hand
