It's impressive how you only read what you want to read when I also provided you with the example of Whitebeard reacting to Oden's presence.
Also, you don't know why Luffy is reacting that way.
- Is it pure fear? I highly doubt, Luffy was never scared of Kizaru in Marineford, never scared of Kaido and BM together.
- Is it fear for his crewmates? Most likely, he warns them as he notices the strong character (Kizaru).
Now, does Luffy know it's Kizaru? The question is irrelevant. If he does, it could be caused by Sabaody PTSD, it could be caused by Marineford PTSD. However, Luffy can be scared for his crewmates simply because a strong character is there (like WB's reaction with Oden), that doesn't mean he is scared of Kizaru himself.
Finally, the only ones that'll be disappointed are admiral fans. Never in any of my arguments I said that Luffy would definitely one shot Kizaru. It's completely bullocks to only have that scenario in mind. I always said that it's one possible scenario but not the only one and Luffy pulling up a good fight with Kizaru is also very likely to happen.
Even if Luffy was to lose against Kizaru, I wouldn't be disappointed. On the opposite, I would be more happy that Luffy experiences this loss rather than the opposite.
So I can't be disappointed when any scenario is going to satisfy me, as long as it's properly written.
I have no agenda in my head as I'm discussing this, you have to keep this in mind.
I'm purely analyzing how Oda writes and while doing so, something is telling me that this fight has the risk of ending like Shanks vs Kid.