There are actually two similar but distinct interpretations of "ashamed" and "embarrassed." One implies that there is direct personal responsibility involved, as in "you deliberately lied to me, so you should be ashamed of yourself." The other is essentially the opposite of feeling pride, and doesn't imply any personal responsibility, as in "I'm ashamed that my school would make such bad decisions."

You're assuming the first interpretation, but one could, through application of the principle of charity, assume the second interpretation.