I have no idea how these results are reported to the state headquarters.
Once they have all the results in an air gapped computer system the results could be called in or even brought to another machine by what is often referred to as 'sneaker net.' This is when it is placed on a thumb drive or other media and brought to another machine to transfer.
The census went fairly easy for me online. My two letters with the 12 digit code was misplaced so there was a provision for an address.
Sure, it wasn't pretty and sexy, but it is likely something that the majority of people can handle whether they are entering the information via phone, pad, laptop or desktop computer no matter what browser a person might choose to use. That is a major consideration when we have so much variety in our technology today. Most of the time my machine is running two browsers simultaneously. Some sites load better in Safari, some do better with Chrome. My Firefox is so old it seems to have a problem with everything.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)