Massage isn't clinical- it's one person giving some form of nurturing touch to another- either in a sports arena, a professional office- or a hotel room. Even two straight men with no sexual attraction whatsoever are in the same model- one receiving care/therapy that has a purpose of physical benefits- relaxation, muscle or tissue improvement, posture/alignment and stretching, etc. This does not have to be a sexual exchange. Once you realize that, you can fully relax and put yourselves in the hands of the driver, and let him/her steer you towards healthytown.
Rather than giving an absolute no to either gender, I'd prefer to chose who to whom I will entrust the healing power of touch. I would prefer to choose the therapist, just like choosing a tattoo artist, or a doctor, or my repeat barber. And any therapist, male or female, who is experienced, isn't going to be offended by a bare butt- that comes with the territory. Instead, its about the creation of a safe place and safe space where the client can most benefit.
If I am the paying customer I would like to not be limited in the scope of the work. I have had massages before where the therapist will skip the glutes, for example, or see the lower abdomen and groin as the DMZ - which kills the energy flow, and can create a spot where toxins and stress will flow into the muscle pockets, rather than being driven down the limbs (arms and legs) and out of the body. Equally as bad is when the energy (or pain, or tightened muscles, or strain) is moving, but stops at a different place. Sadly, in western culture men have become socialized to all but eliminate male-male touch.
I would prefer the therapist to use his/her best skill- meaning not being made to feel uncomfortable about incidental touch, or unintentional arousal. I would prefer to not be draped with a towel or a sheet due to modesty or state statutes. And I don't want to incite some sort of incident by my body responding to increased blood flow in the tissues, which is the whole goal of the massage. Ground rules would normally be established before we start, but for my comfort I would usually prefer another man- because then I can fully relax and not be preoccupied by my body's natural function.
If some guys are just more comfortable with a masseuse, I think he should be encouraged to hire a woman, because he will be less stressed about being intimately touched by a man. And vice-versa. But moreover i'd say to remember that the hands on you are connected to another person who has feelings and should be treated with respect and consideration. Bottom line is that the massage is gonna be much more useful and fulfilling when skilled hands brings healing and relaxation, and the pent-up stress can be released.