Learning about group dynamics and social situations is probably the most important part of middle/high school, and more often then not homeschooled kids are at a disadvantage in these situations when they finish school then when compared to non-homeschooled kids.

This isn't always the case, and social awkwardness can go away after x amount of time, but I know that I am glad I wasn't homeschooled despite the occasional bad experiences at high school. Knowing how to deal with people face to face is an extremely important skill.