Gadamer following Heidegger argues that the hermeneutic circle is not "vicious."
Yet the typical literary critic chooses an approach, applies it to the text, and finds what sh/e expected to find. In other words, the circle is completely vicious.
A theoretical approach, essentially a previous interpretation, determines what the critic is going to find. S/he reads the text mostly in order to confirm a previous bias. Every piece of evidence confirming the interpretative prejudice serves to reinforce the global interpretation, so the oscillation between part and whole only makes the reasoning more circular. The text never catches up the reader short, never surprises. We've all seen this happen with our graduate students, even worse with the undergraduates. Half the time when we say that the student's interpretation is wrong, we are not being dogmatic (insisting on our own interpretation), but noting that the student has never listened to what the text is actually saying. Mature scholars do the same. To even say you have an approach means that you will be victim to confirmation bias. To say "I am a Freudian critic" means that you will interpret in that way.
So Gadamer is actually not describing how people do interpret, but offering an ideal version of what they should be doing: treat the circle as open rather than as vicious. Be surprised. Question your own prejudices.
I am not exempting myself from this critique of literary criticism. I think it would be presumptuous. If someone else tell me I am listening to the text, I will believe this, but I cannot be sure I can do this unless someone looks critically at what I am doing.