This is a great topic. A thesis is your main point. A good thesis has many solid supporting points. With this said, how about the following thesis: Beauty pageants are not innocuous events but psychologically damaging to both participants and viewers.
There can be many supporting points. First, you can say that pageants objectify women and for this reason you are only looking at outward beauty. Even the interview portions are short and lack depth. Second, pageants cause women to conform to a certain standards of beauty, which destroys their individuality. For example, all participants are tall and skinny. Third, you can also say that pageants harm viewers, because it causes younger girls to aspire to an unattainable standard, which may give many eating disorders and other body image problems. It also harms men, because they may unwittingly encourage a false sense of beauty.