“If this is true, why didnt her thesis instructor catch it?”
Advisor. He or she is an advisor. They can’t possibly be expected to catch all of these issues unless they know where it’s lifted from. He or she is a full professor perhaps with a teaching load, other graduate students, writings/research of his/own.
And you are most concerned with the actual thesis and conclusion.
There is a chance it should have been caught before committee but even then it’s difficult.
Her dissertation is not the first nor will it be the last to have lifted passages from another source without attribution.
Thanks, yes the correct word is ‘adviser’.