Been a sports fan all my life as well and I don't think the idea of a mascot is to carry the team / fandom nor did i mean to imply that. Rather they can be a source of entertainment and for some people it does provide fond memories, feelings and pride. You can both be a die hard x's and o's fan and also enjoy the entertainment factor - minor league baseball sure seems to think it helps.
It is a part of the experience a good athletic (ie entertainment) program should be trying to create as they look to capture every dollar they can from the local public. The music, the scoreboard, Grange Grove, team walk, mascot (if so inclined) etc.
I get that you personally don't need/like it - but there are many kids, young adults, and not so young adults that, if done right, can find some enjoyment, pride from it.
I am taking a wild guess you also don't enjoy DisneyWorld. However, that type of draw (how I wish my kids didn't want to stand in line to get an autograph with a character) can be pretty emotional when done right. For example, many fell in love with a white guy performing the role of a native American and dancing around on a hardwood floor.