Lucius was getting annoyed. Draco may have been from a time in Lucius's future, may have knowledge that Lucius did not, but that was certainly no excuse to speak to him with such disrespect.
"Of course I meant it," Lucius hissed, his displeasure evident in the privacy of the pub. "If there is much to tell me, you had better get started. And watch your tone with me."