If you read the actual letters, you'll see they ask for
"the name, address, length of service, and electronic communications transactional records for all services, as well as all accounts, provided to the individual(s) or identifier(s) listed below."
The letter explicitly says not to provide information "that would disclose the content of any electronic communication".
Not all user-generated content on Twitter is public. I couldn't possibly know what kinds of transactional records have been requested or the distribution therein, but DMs seem like plausible targets.
"the name, address, length of service, and electronic communications transactional records for all services, as well as all accounts, provided to the individual(s) or identifier(s) listed below."
The letter explicitly says not to provide information "that would disclose the content of any electronic communication".