I assume he means at the device level.
If so, it's on their servers and there's no "networking" you can do to know whether they forwarded it on from there.
So not that many jumps from what I described.
Because you can doesn't mean you have to, especially when you don't actually have any knowledge on the topic at hand. (And, as people have pointed out, this is both a weird and incorrect assumption, adding nothing to the discussion other than confusion.)
What's worse is that I don't think it actually works how you've assumed. The drone has no internet connection itself, the software is instead pulling the files down over wifi, which is something the standard software supports if the drone is close enough. This is the "no need to export from your DJI device" - LightCut can presumably access the drone files directly. None of this requires uploading the videos to anywhere, and doing that wouldn't even make sense - these are large video files, people would notice their data plans being ravaged by multi-gig uploads every time they flew their drone.
As far as being condescending, I think that's less of a negative trait than offering unbacked "I don't know, but" comments which add no value to the discussion.
I did consider the value of my own comment at the time, but I think there is a big problem in tech discussion with people with no actual experience or relevant knowledge feeling that their off-the-cuff suppositions are as welcome and useful as meaningful input from people with direct experience, and highlighting this behaviour as negative and unwelcome is worth risking the inevitable backlash in response.
Holy irony man