I get the direction that the video was going on... but all it did in my mind was prove that it was completely possible. 5k solarpanels, two full football fields or 17 small nuclear reactors is all that is required for the process? I would have thought it'd be more.
I get what you're saying... it will be hard... for sure... Is it possible in the timeframes being discussed? probably not. Is it an endevor for our generation to embark on? yes. It's the greatest adventure ever written, and yeah... it's gunna suck for all people involved. It's a hostile wasteland.
With that out of the way... I think the video you linked tells the story dishonestly. The deltav required to get from mars, nor to the moon back to the ISS, is no where near refilling a full tank. Without a retro burn, it would require around 1/8th of the deltaV.
Secondly, you can send 10, 20 starships before, or each cycle and spin up. No one is saying that the very first time you send people they will use Insitu 100%. Maybe they bring the hydrogen, or the carbon dioxide and try and get a plant going. Or they can send all the fuel required beforehand. Once they have some kind of more permanant presence, they can slowly ramp up and take a more and more of the process on.
Not all these projects need to be solved at once. With 100T carrying capacity of each starship, all the youtube video convinced me of that it will take around 30-40 starships... which isn't that wild.
I would be more interested in what you think about the more advanced manufacturing, despite all the problems and infrastructure required?