It's a question of choice, as a user. My original question was - why? Saving Earth, that's one way to look at the thing. Why then, amazon.com connects just fine with 256 bit cipher, but then fails when one goes to personal recommentations section. Most likely, of course, it's a misconfiguration issue, but is it possible that there exist more sinister reasons?

Recall RC4. We now consider it broken. But it is still allowed on many servers, and even on 34.0.5 Firefox.

I agree, when one goes to disable legacy functionality, one should be prepared to suffer consequences. That's why my original question was "why".

When both AES-256 and AES-128 are enabled, many servers prefer AES-128 because "it's faster".