As such I agree that Firefox refusing to implement things like WebSerial and WebHID is shooting themselves in the foot, and will only drive more users towards Blink.
You could have made your point in a less inflammatory way, though.
https://mozilla.github.io/standards-positions/#webserial
Allowing serial but not HID would be really strange. With HID you get standard identifiers that let you filter out devices that are too dangerous for the web. With serial you get nothing. Even if you know a device is dangerous, there's no way to protect users from it.