I have a few misgivings...but I usually do. I don't like her being really angry towards her X. Anger or hate is not the opposite of love. In my opinion women that aren't interested in a guy are completely indifferent to them...or maybe grossed out. Women...care to chime in on that? To have such strong emotions about him aren't "right" as she puts it.
It's fine if she wants to go slow, but I think while you are being "patient" that you also practice a little more of the focusing on yourself. I think continuing to move forward is probably the better plan. You'll eventually resent her slow pace if you are waiting for her to get off the snide. She's taking steps back from you...or at least no steps towards you. I'd give her more space while you pursue other interests to a greater extent. Being the one more committed to the relationship puts you in an awkward and weak position, kind of like an LBS. Just my thoughts.
You cannot be lonely if you like the person you're alone with. Dr. Wayne Dyer