@feoh don't want to sound harsh too but:
"Carbon makes it easy to create and share beautiful images of your source code. "
It will inevitably put you on the side road. :/
But maybe twitter/mastodon could enforce/remind users to fill in the ALT tag with a comprehensive line for disabled people.
But please, don't go on the "woke" trend of complaining for everything.
"carbon-ed" tweets are simply not for everyone one. To be honest, you won't miss anything anyway. :)