Most of the homeschooling families that I have experienced do not seek to completely shelter their children from all the bad things in the world. Taking the bullying example, the goal is not to protect their kids from ever experiencing bullying. Instead they are trying to provide a structured environment for their children to develop while gradually exposing them to more challenging people/situations as they become prepared to handle them.

When teaching a child to swim, you don't typically throw them into the deep end of the pool, but instead start out in a shallow structured situation until they have learned the basics.

if bullying in school is necessary for kids to learn how to cope with adult life then most children are going to fail, because most of them will not experience any bullying. so how does that help?

i must therefore disagree with that premise. i was bullied (thankfully just mildly) in school, and i learned nothing from it that would have been useful later.

what we need to kids to learn is that bullying is not part of life and should not be tolerated anywhere, but should be stopped whereever possible. if we want to help children then not by letting them learn how to cope with being bullied, but teaching all children how to not be a bully, and how to recognize when others are being bullied, and how to help both the one being bullied, as well as the bully, who may well act out because they are themselves coming from a difficult situation eg at home.

doing that in a school requires active involvement from teachers and parents. absent that, going to school doesn't provide any benefit on that issue.

So is dying, are you going to force kids to practice that too?

Bullying is real, but there is no damn reason to force little kids into it.

A lot of the "socialization" you learn in school is very dissimilar to "real life" though.

I don't know many workplaces that are organized into teams of 25 employees all the exact same age with just one single supervisor decades older as the sole person they spend much time with that isn't their exact age.

School's great weakness regarding socialization is it mostly teaches people how to get along with others who are the exact same age. It overemphasizes this and creates a strange cultural bubble where kids (and later young adults) are overly disconnected from the culture of older and younger generations. So much of what kids "learn" in school is from being around each other-- and what do other kids know? Not much, either. This is the blind leading the blind.

There is no good reason for this, it's just an artifact of running schools in a seemingly cost efficient way. But because we've grown up with it for a few generations now, many of us will try to justify segregating people by exact age as natural and valuable in and of itself, when it's not.

If schools mixed ages more, I'd be willing to consider school "good for socialization" but there is very little about the school environment that resembles anywhere most kids will have to spend a lot of time in as adults, especially successful ones.