lmao - wrong end of the stick entirely.
He's not talking about something that prints ay 270 but something that - once printed - can take 270c as an external environmental temperature.

'carbon fibre' filament - unless that used by markforged for continuous fibre reinforcement - is simply abs or pla with bits of carbon fibre mixed into the filament.
Can't imagine why it would ever need to be extruded at 260c unless maybe it was mixed with polycarbonate ?