Every limitation I have seen is 10 kts, so that is likely pretty common. As a matter of fact, the 10 kt limit was even mentioned in an article about the American Airlines aircraft that recently ran off the runway. FWIW, the report was that he was offered the opposite direction for wind and declined.

I disagree with the concept that they don't need to be familiar with tailwind limitations. First of all, THEY set the duty runway. They need to know something about aircraft performance to do that.

As far as it being a simple matter of pilot responsibility, I'd invite you request an opposite direction landing during the nightly inbound rush at MEM and see how long it takes to get on the ground. I agree that the PIC is the ultimate responsible party, but expecting ATC to set the runway in use without regard to tailwind limitations is expecting the responsible pilots to orbit for a while.