So, yes, it is easy to guarantee that a mass database of biometric data isn't abused if you can prevent it from being gathered. We're making no efforts in that direction, so we're running every day towards a future in which the holder of such a database can deepfake anyone doing anything.
Which is why it's so strange to say that one of the greatest risks of the TSA's program is that they could do a totally different program in the future. It's literally like saying that going to the gym is risky because you might get into BASE jumping.
There are better arguments. Hence, this piece is weak.
It effectively means that if I don't want them to potentially give it to LEOs, I have to opt out of any services they are gatekeeping behind it.
That's not a slippery slope argument, it's an argument that there is no way for me to review how the information they collect is actually being used.
There seems to be little resistance to this in the USA, and we’re also okay with abysmally bad forms of identification (SSN, birth certificates).