They probably assumed everyone using Mac is using Safari. I have seen lots of code shared on programming forums that simply check for Mac and assume the person is using Safari.
Then you should read better "programming forums", because I haven't seen anything like that since the late 1990s, and it's preposterous to think that something produced with this level of quality would commit such atrocities.
Also, it does work on Chrome, Chromium, Firefox.
One of those forums was Stackoverflow. I don't know a better programming Q&A forum than SO. Please share so that I can switch to them.
It's not a mac problem. I'm on a mac. The site doesn't work in Chrome, but it does work in Safari.
The site didn't work for Chrome on Ubuntu either with the same version. Firefox on Ubuntu worked though.
No, same problem here with latest Chrome on Windows 10.