Even if they were hacked - and it's known - it's a good reason to ban them (provided they aren't self aware). I mean, it means that if they don't have a decent "firewall" your plastic pal who's fun to be with could turn around and snap your neck in a second. Who wants to deal with that.
I saw no evidence in the short scene that the type of synths shown was self-aware. Just because it looks like a human doesn't mean it has a consciousness - any more than the Horta looking nothing like a human meant that it lacked a consciousness.
Still doesn't explain why Picard allows himself to be baited into that corner by the reporter.
The reporter says, and I quote:
Reporter:
"A group of rogue synthetics dropped the planetary defense shields and hacked Mars's own defense net...92,143 lives were lost, which led to a ban on synthetics."
Picard:
"Yes. We still don't know why the synthetics went rogue and did what they did that day, but I believe the subsequent decision to ban synthetic
life forms was a mistake."
Reporter:
"Lt. Cmdr Data, operations officer the Enterprise, was synthetic. Did you ever lose faith in him?"
Picard:
"Never."
First: Semantics. Synthetic
life forms. Picard respects all forms of life. If he felt they are indeed life forms, then he would NEVER have condoned the Federation's decision to use them. He'd also be condemning them to this day. His use of the words themselves indicates he believes they are not simply machines, but life forms. So him not even bringing up their misuse is out of character.
Ok, so...IF these synthetics were as you say, just computer systems, and we just go along with Picard viewing them as machines, why doesn't he say something like, "whoa whoa whoa, wait just a minute here. Data was a sentient android, not a synthetic. There's a difference."
I believe this is the part where Picard should have instead of saying "the subsequent decision to ban synthetic life forms was a mistake," to, "the decision to abuse synthetic life forms was a mistake"
So many character holes here.