Tortured being defined as solitary confinement and terrible conditions, not like legitimate torture that happened in places like Abu Gharib.
If the UN has defined it as torture, then I feel reasonably confident saying it's "legitimate torture".
Yes, I'm sure many people have been "more tortured" by the US government (or other governments) than Chelsea Manning -- but it doesn't change the fact she was tortured.
[1]: https://www.theguardian.com/world/2012/mar/12/bradley-mannin...