How do you tell people about nonfree JavaScript?
How do you tell people that no, you will not run that web program, because it is proprietary software? People often don't even know what proprietary software is, let alone know that web programs are proprietary software.
People don't usually ask me to run web programs. A couple of times last year someone sent me a link to some Google documents, expecting me to log into a Google account and download them. I just emailed them and said I don't have an account, please send me the documents directly.