Despite the use case for censorship circumvention, many malware command and control bots use domain fronting to bypass corporate web filters that otherwise might block their traffic. CloudFlare, being a security-focused CDN, most definitely does not want to help enable malware authors to bypass security.
Russia had no problem whatsoever blocking both of them when blocking Tether a couple weeks ago.
No problem? They crippled their own use of the internet, at huge financial cost.
Where do you get that from? The Russian government blocked lots of AWS and Google IPs, and had no problem keeping them blocked until they agreed to stop allowing this, which was the same thing Telegram was using. And it doesn't appear that they cared about the "huge financial cost".