This hypothesis is interesting. You say, her anxiety has a different cause, since you too had anxiety, even though you did not have similar experiences. So, the hypothesis you have is - "Anxiety has a common cause for you both which she is apparently not seeing yet"
Well then, you are missing the forest for the trees. Don't we all love to bucket things in strict black and white, to make decisions easier? Fact is, anxiety has multitudes of causes. You may, at some layer/level, as you go higher/roll up, think you can generalize and put a label on the common cause, similar to how all rivers eventually lead to the sea.
Might or might not be true, some rivers just run dry, which means we overestimate our capacity to "generalize and taking all the intermediary inputs as they should mean, to form a coherent equation", when in reality we have made wrong assumptions/unconscious omissions
Coming back, this means even though some of her anxiety might be due to the common factor 'x' in you both, 'x' might not impact her as much as it impacts you, and most of her anxiety might be due to 'y' she described above. We are all allowed to have nuances and don't need to conform to common metaphorical behavioural kumbaya expected by society
Why the rant? - cause these generalised statements although harmless at a surface level, cause the sufferers to doubt themselves and spiral down further, whilst they should have been focusing on recovery.
Sometimes we all need to keep in check our egos/fears, which will inturn automatically reduce the barriers to tuning up our empathy that's been suppressed by these doubts, so that we can be aware of our Sampling and Selection biases (or any other for that matter) that cause us to generalize too quickly and unintentionally cause harm