Whatever negative feelings you experience during a Yoga session or while performing any meditative practice aren't the result of the practice itself, the practice merely reveals what you already have within you and, once revealed, you can do something about it, that's the essence and point of these exercises. The harm arises from internal pressure and resistance, not from the work you do to release them.
Yoga indeed isn't for everybody... at a certain level of expertise. Like any other practice, it requires training and a certain physical condition that can only be acquired through consistent work, it can't be accomplished with just a few attempts, but even disabled individuals can engage in Yoga in accordance to their capabilities, the most difficult poses aren't a requirement to obtain the benefits.
Women are more commonly attracted to these studies, but it has very little to do with their weight, it's more about connection with emotions, which men often shy away from. As you said, there are many members here with an established practice whose experiences you could include in your research of the topic. Here are some of them: 
RE: Yoga isn't that Good for you