RMS emails in restaurants, cars, trains, etc., in Europe and the United States but also frequently in SE Asia and South America. There are pictures of him responding to email in the mountains in Nepal.
It's easy to get Internet access on the go in most of the places I've been to, but I've been to a tiny fraction of the places RMS has been to.
Surely you can't expect people to take this argument seriously. It's easy to get internet access on the go in much of the world already.