Why are males expected to take their shirts off during OMM?

I mean it's almost like they don't even ask, they just expect you to take your shirt. In some cases instructors even told us to take them off to "feel the fascia". I'm usually sweating excessively, I'm overweight and I don't feel comfortable standing all sweaty with upper part of the body naked in front of the class of non sweaty people. Besides, my partner would probably wish that I left my shirt on after touching my sweaty oily skin. I think it would be best for everyone to let males... Why are males expected to take their shirts off during OMM?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums