That's the "reflexive" part: Americans often think of "freedom" in either an extremely simplistic way ("I can do whatever I want, whenever I want! Up yours, government! Instant gratification all the way! Free speech means I can say whatever asinine thing I want, anywhere and anytime, without giving a crap about others!") or a nationalist / jingoist way ("we have freedom and they don't! USA! USA!").
(Of course, not everyone conceptualizes "freedom" this way in the US, but it's a depressingly common approach - especially where any sort of political discourse is concerned.)
The reflexive part is that any time our personal space (emotional, mental, or physical) is threatened, it is a reflex to retaliate with "you are violating my freedom" style response.
To ideas that threaten: "You can't make me think that way, I am free to think as I want"
To feelings of discomfort: "It's a free country, I shouldn't have to feel this way"
To physical space: "this is me or my property, I can do what I want with it"
Obviously, when taken in extremes this results in polarization, mischaracterization, and ignorance. Taken responsibly, it is also not appreciably different from any place with a bill of rights. To americans, I would level the criticism that we use it as a crutch and an excuse, more than an ethos, as evidenced that most appeals to freedom are also appeals to the value of self interest.
(Of course, not everyone conceptualizes "freedom" this way in the US, but it's a depressingly common approach - especially where any sort of political discourse is concerned.)