They developed and tested their software on Macs. Yet they offered it to Windows and Linux customers without ever doing any testing on those platforms? Isn't that like saying my React app works on IE-11 so I'm sure it must work on IE-6?
I mean, in the sense that technically when you publish anything on GitHub/npm/PyPI/RubyGems/etc. you're "offering" it to Windows and Linux users – sure. Given that the editor plugin is not a standalone software product being sold, it seems perfectly reasonable to just put it out there and then let people report issues on their platform.