I used to be part of a crew that installed cell towers and on-building cell antennas. Granted, that was in 2000, so technology may have changed. But, the computers needed to run each installation were the size of the average pickup truck bed, and drew so much power they needed special heavy-duty cables to handle the load.
And that was for non-smart flip-phones.
Pretty sure your friend is right. Those installations would probably draw enough power to make a dent in the electrical supply.
I’m the last guy to know the facts about the story and you worked on them yourself so I will defer.
“The wireless infrastructure landscape in the US showed 142,100 cell towers and 452,200 outdoor small cell nodes across the country at the end of 2022.”
327 million cell phones in use in the US.
Charging a phone once a day will use about 0.15 kilowatt-hours of electricity per month and 1.83 kilowatt-hours of electricity per year.
So maybe my friend wasn’t onto a significant power drain source?