I'd definitely pick Germany. Actually, I'd pick Netherland, because that's where kids are apparently the happiest in the world, but Germany sounds like a great alternative.
And grandparents nearby is a boon to any young parent.
I've heard in Germany (and Europe in general) you'll forever be a stranger, while America is more of a melting pot and immigrants are allowed to become Americans.
I think it's more important how you dress than the color of your skin. If you dress in your home country's traditional clothes, you will probably experience more hostility than when you are wearing western clothes. The color of your skin will also be a factor, certainly more so than in the US, but usually hostility is based on your assumed (based on your looks) religion and values than the actual skin color. In the end, people are tribal, in rural Germany more so than in cities, and whether they accept you and how they treat you depends on whether they can relate to you.
I think language is the main factor why immigrants often will be strangers forever. Your social circle will be very limited if you don't speak German near-perfectly. But I would assume the same in the US if you don't speak English very well, and even then it's very difficult. At least that's what I have heard from Germans who moved to the US.
In bigger cities there are usually local expat communities where English is spoken, but you won't find many in rural Germany (unless you are close to a US military base or similar things). I think the best way to find them is on Facebook.
Some would go as far as to say that there is good feelings for those who try to speak the language after all, most Americans were immigrants a few generations back.
That doesn't mean it's safer, and we still often struggle with delivering health care, but it's a weirdly welcoming place.
You sure about that. Out police force is known for being more liberal about shooting people based on skin color. I'm not German so I won't argue with you but I don't get the impression that there's as much institutional racism there.
How much you will truly be accepted depends a lot on where you are. Some places, like New York or Amsterdam, are very cosmopolitan. Rural areas often a lot less so. Munich probably more than the Bavarian country side.
What is the rationale for this?
Heck, a neighbor's small daughter crashed her bike and started crying near me. I went out to help and immediately turned around as a 25 year old dude because honestly I didn't want to go to jail. It's essentially impossible to be a single man alone in the presence of a small child. It's way too risky these days.
We've fallen to commoditization of "the village" services. No more are people taking care of neighbors children out of friendship or helping someone build a fence, etc. We now pay for everything and with that, our duty to our fellow neighbors/man/even family has eroded. We're isolating and compartmentalizing every relationship and every interaction and I personally believe it's the doom of our cooperation as a people in the US.