For example, here's a fact that may surprise religious traditionalists who feel under siege. Take all the hate crimes perpetrated against Jews. Add all the hate crimes perpetrated against Muslims. Add all the hate crimes perpetrated against Christians. Add all the hate crimes perpetrated against all other religious groups too.

Combine all those hate crimes in 2013, the most recent year data is available.

The number of hate crimes perpetrated against gays that year is still higher, despite the fact that religious people far outnumber gays. So if you're gay and looking at your Facebook feed, it will likely include controversies about whether Christians should be punished for not selling stuff to same-sex weddings. But instead of seeing such controversies as would a traditionalist who, rationally or not, earnestly fears for his job or the future of his family business, you're more likely to see them through the lens of prejudices and risks that you face. If you pay attention to the fact that gays like you are victimized, your Facebook feed might include these stories:

All those articles are from the first few days of this month.

In turn, people whose media consumption skews toward stories like these are comparatively unlikely to have been exposed to or reflected upon the worries of Christians targeted for their religious beliefs by antagonistic supervisors at work; academic hiring committees that look askance at candidates who are openly religious; or Child Protective Services caseworkers whose prejudice against religious parents causes them to wrongfully remove kids from such households.

I could go on and on citing instances of both groups being mistreated.

But the point of this exercise isn't to pit the unjust treatment of religious traditionalists against the unjust treatment of gays (or vice versa) and to decide who has it worse. Nor is it to assert equivalence between the abuses each group has faced. Readers may disagree about that calculus—but that doesn't matter here.

What everyone ought to be able to understand is why some members of both groups feel under siege—and why members of both groups understandably don't always empathize with one another. It is due to the fact that there is no such thing as a fully shared American culture: Life here is an amalgam of lots of subcultures that only partially overlap. People pay disproportionate attention to what affects them personally.

Americans receive different upbringings in different families of different faiths, while living in different neighborhoods of different cities in different regions, and are then thrown onto the same social-media platforms. These platforms afford an illusion of a single culture, as if public controversies are grounded in common experiences and assumptions. But Americans have never understood one another.