Mr Smith, as a sceptic, prove it by demonstration. Or pack up your bags and go water devining! No demonstration on spoofing of an ADS-B signal has yet taken place anywhere in the world.
I know of a number of occasions where someone has spoofed the transmissions of ATC using handheld radios causing a lot of obvious problems, requiring an ATIS message to warn all users to change frequency and disregard transmissions on published frequency. Yet, there is no ban on handheld devices.
Come clean, Mr Smith. Why are you so against 1090ES ADS-B?