Well, I personally never used that as an argument. It wouldn't even make sense to begin with, since Marco was a kid at that point in time.
I am not denying that Luffy's reaction is a testament of Kizaru's power and threat-level, it's just that Luffy wasn't concerned for himself. Obviously, a top tier appearing out of nowhere and posing a threat to everyone around, including his crew, is something that would concern Luffy, just as Shanks was concerned seeing how Kidd was about to annihilate those fodder captains he held concern for and just as Whitebeard was concerned about a strong enemy approaching his crew.
But Luffy already proved that he isn't concerned for himself. He faced 3 admirals at once pre TS, he attacked Fujitora when he had but basic Haki and even after being sent flying by Fujitora's raging tiger, wanted to go on with the fight. When Ryokugyu assaulted Momo and the Retainers, Luffy was watching the fight with amusement, while Yamato stated that they should call Luffy and the others, as they are better than Ryokugyu.
There is absolutely no basis for thinking Luffy is concerned for his own well being. Lol.