So have him explain How and Why it works - if he has been going this for 20 years. I would think he can explain why it does.
Do you want to know WHY it has nothing to do with it?
That cache is just files on your disk just like any other file on your disk, they are NOT loaded into memory, nor or they even accessed unless your BROWSER calls for them.. Is you browser open while its playing your game? Doubt it, so why would the files be even accessed? Again they would only be accessed when say you went to neowin, and the logo.jpg was called to be loaded - vs downloading it yet again you would just load it from cache on your disk.
Now since those file are not being accessed, so your disk is not having to move to load them, nor are they loaded into memory.. How in the world would some files sitting on your disk which might as well be say your resume or your homework in your documents directory for all it matters. Have anything to do with how fast your computer can ping some other server over the net?
Your disk is not accessing stuff it does not need to, your ram is not loaded with extra stuff, your cpu isn't doing or caring about the files sitting there.. So how in the world would they effect the latency between your computer and some server on the net. Or how would they in any shape or form have an effect on how resources are allocated to the game your playing?
If he thinks some file on your disk be it loaded or even being accessed at the time you send the packet could effect how a fast a packet travels across the net, or if it makes it or gets lost he clearly does not have clue one to wtf he is talking about.. But would love to hear him explain it