"I haven’t looked at Flutter for other platforms than web so I cannot comment on it other than that the general principle of Flutter is a terrible idea."
The author completely missed the point of Flutter. It is a mobile-first platform positioned as an alternative to ReactNative. Its main goal was to provide a way to build cross-platform iOS/Android mobile apps with a minimal performance trade-off. For example, its code is compiled into native machine code for iOS, Android, and desktop. Its apps tend to be more lightweight and feel snappier. Unlike ReactNative they do their own rendering so that you can have pixel-perfect consistency across platforms.
Flutter's web and desktop support is more of an experiment and a convenience for those who want to port their existing mobile apps to web and desktop.
ReactNative was targeted for web developers who want to port their existing apps to mobile, Flutter's web support is the reverse of that.
The author completely missed the point of Flutter. It is a mobile-first platform positioned as an alternative to ReactNative. Its main goal was to provide a way to build cross-platform iOS/Android mobile apps with a minimal performance trade-off. For example, its code is compiled into native machine code for iOS, Android, and desktop. Its apps tend to be more lightweight and feel snappier. Unlike ReactNative they do their own rendering so that you can have pixel-perfect consistency across platforms.
Flutter's web and desktop support is more of an experiment and a convenience for those who want to port their existing mobile apps to web and desktop.
ReactNative was targeted for web developers who want to port their existing apps to mobile, Flutter's web support is the reverse of that.