It is a fair point Sarah but I think there is more to this.
I think GGs who are open to learn about CDing and seek acceptance actively seek out information and so soon discover that full emulation is common among CDs. That means the GG is already aware of where this is likely to end up whether or not the CD is aware of his own extent or ready to admit to it. This makes talking about the subject so much easier.
Communication is about holding hands together. Sarah, your learning and attitude meant your SO could feel confident about being 100% open. If you were instead reticent about the subject and were not interested in learning about it, would your SO have still been 100% truthful and open?
One thing I have to keep reminding myself is that other people's behavior towards me is actually a reflection of their perception of who I am. How I behave and present myself modifies how others treat me. Now their perceptions of me may be wrong but does that not indicate that I am not doing a good job informing them about my true thoughts and feelings and giving the right signals to open communications?
I believe CDs who take the baby steps route do so because they lack confidence that their SO will react in a reasonable and empathetic manner. There has to be a reason why they fear the worst and so decide baby steps are the best approach.
It is understandable that a GG who is likely in state of shock, confusion, and filled with society's transphobic ideas, is unlikely to be able to communicate and convince their SO that they are able and willing to discuss the whole truth.
So by all means critic the baby steps strategy and point out its problems but keep in mind CDs decide upon that approach for a reason.