Sorry. The movies do a bad job portraying that she's a vagrant rather than someone purposefully traded away. And the novels do not count. If you have to go outside the movie to make the movie make sense, you failed. That's another major failing of the prequels that applies here.
Then why were people making that argument in the first place? And that just further cements how incompetent the First Order is since Phasma didn't notice the soldier having a panic attack and taking his helmet off needs to be escorted straight to re-education.