If you’re home-schooled, then how do you make childhood friends? How do you meet that dreamy girl, that you remember after all these years, just because she did something nice for you once.

You meet kids in your co-op. Or in your extracurricular activities (if you don't have access to non-school-related options like karate classes, dance classes, community sports leagues, etc., plenty of school systems still permit homeschooled kids to register for their extracurricular programs). Or by hanging out with your parents' friends kids. Or by playing with other kids in the neighborhood after school.

   While public schooling does have its drawbacks, and some bad bullying scenarios (we’ve all been there), it also does have some good things. And you meet a variety of other kids, that comes from different walks of life, that may positively (or negatively) influence your own life.

Yes, it does. And for some people, public school is the best option. One of my sisters, for example, has a mix of kids in public school, private school, and homeschooling, because each of them has different needs and different approaches to schooling have ended up working out better for each child. But the fact that each option has its strengths does not mean that homeschooling is deficient.

    Sure, you can supplement your kid’s social activities with going to church, or karate, or ballet, or piano, or other extracurricular activities, but it’s not quite the same.

Of course it's not the same. That's the whole point. But "not the same" does not mean "worse".

    Church, for one, is too cohesive, and results in groupthink.

Depends on your church.

    And that’s if you really want your kid to worship a bible, instead of understanding science.

Again, depends on your church. I grew up in a religious family, and made many friends through church, but I still got degrees in two scientific fields, as did several of my siblings, and I don't think you could accuse any of us of "worshiping a bible" or "not understanding science".

    The other extracurricular activities on the other hand, lacks cohesion, that you don’t build lifelong friendships through that.

You have no evidence for that. My nieces and nephews, and homeschoolers I know of my own generation, would say exactly the opposite.

   The other thing is, home-schooling tends to shelter your kids.

No. Homeschooling is sometimes used as a tool b people who want to shelter their kids to give them greater control. But it does not in and of itself result in excessive sheltering. Some of my niblings have online homeschool classes with kids from all over the country, with way more diversity than they would get in their local public schools.