This is not "catering to the lowest common denominator." That expression would be appropriate if CloudFlare decided to keep everyone on SHA-1 just because less

This is not "catering to the lowest common denominator." That expression would be appropriate if CloudFlare decided to keep everyone on SHA-1 just because less than 2% of users couldn't use SHA-2. But that's not what they're planning to do. The 98% of users that support SHA-2 will be given SHA-2 certificates. Your argument about Windows XP is moot because XP SP3 can handle SHA-2 certificates just fine. So even if we got rid of SHA-1 now, people will still be running XP SP3 10 years from now. I used to have a Nexus One that ran Android 2.3. I didn't curse Google or HTC when it became too old to be useful. I don't think people will curse Huawei or Xiaomi, either. We're getting used to planned obsolescence, the exceptionally long life of Windows XP notwithstanding.