I'm homeschooled and I'm not fragile. I know a lot of men and women who were homeschooled and they aren't fragile either. Being frequently bullied may be one way to learn about life, but it isn't the only way. In fact I don't think it's even the best way.
> What's to prepare them for that when they're homeschooled?
Life. The homeschoolers I know do tons of things that help them explore life. There are too many to list here, but here's a short list of excellent things homeschoolers do that incidentally help them learn about life: dancing (contra, waltz, swing, etc.); running your own lawn care company; babysitting special needs children; babysitting in general; mission trips to foreign countries; film-making (for fun, commercials, competitions, etc.); learning to fly airplanes; regional equivalents of boy scouts (4H, boy scouts, something else that I can't remember the name of); and much more.
I work in a .NET C# environment and I get all of these issues. Sorted in order of most annoying to least annoying, they would be: #2, #1, #5, #3, #4. I don't really mind 3 and 4. I'm just saying this to affirm that your experience is not unique to you.