Capital-G Gnostic is a noun, and has a different meaning from small-g gnostic used as an adjective to describe a particular type of theist or atheist.
We run into this phenomenon a lot here - somebody citing one of several dictionary definitions for a word, and insisting that the word defined can only be used in the specified way (prescriptive). When people tell others what they mean when they use a word, the proper reaction is to simply note what was said and assimilate the information for the purpose of understanding that speaker or writer. To argue that the word cannot be used in that manner is pointless and incorrect. Words mean what the person using them intends them to mean. If the usage isn't standard, one need only explain how he is using the word. If the person one is dealing with would rather argue about words are allowed to mean, find somebody else to converse with - somebody that is interested in understanding and discussing your thoughts.
Look at how many people on this thread alone (and Dr, Gleiser of the OP) are implicitly or explicitly insisting that the word atheist applies only to people willing to assert that no gods do or can exist, a definition that would exclude most self-identifying atheists.
One gets the impression after awhile that they just aren't interested in what atheists actually have to say as much as telling us what we believe, and getting it wrong. This probably comes from their priests, pastors, preachers, and ministers doing the same thing - telling their congregations what we believe and why, and getting it wrong.
Nothing else really matters apart from the fact that we have desires and beliefs that inform our actions, and that if belief B reliably informs action A such that desired result D is the outcome more consistently than other competing beliefs, then belief B can be called whatever you call useful ideas - true, correct, factual, knowledge - whatever. Concerns about absolute or objective truth are metaphysical time wasters.
What difference does it make what's "really" out there if we can manipulate our experience of it to conform to our preferences? Hologram? Brain-in-a-vat? Last Thursdayism? Descartes' demon? A matrix? The information is neither available to us nor necessary to have. We are irreversibly locked into the theater of our consciousness, experience nothing else directly, and therefore can assign primacy to the subjective conscious content over what we imagine underlies it.
More correctly, the evolutionist sees that blind, unguided nature appears to have the ability to create earth's tree of life without help from an intelligent designer. The evidence for abiogenesis and evolution is not evidence against the possibility or existence of a god or gods. There is still the possibility of gods nudging evolution to proceed in an intended direction, just no reason to believe so.
I hope that you aren't implying that both the creationist and evolutionist are each evaluating evidence properly, yet disagreeing on what it means. The principal difference between faith-based and reason and evidence based thought is that the latter begins by examining the available relevant evidence and derives a tentative conclusion that is tested, whereas the faith-based thinker begins with an insufficiently supported premise accepted on faith, and then sorts through the evidence looking for that which seems to support the faith-based premise. This cherry-picked evidence is then front-loaded before the premise, which is then offered as a conclusion derived from that evidence - something I call a pseudo-conclusion.
As just indicated, I'd say that the opposite is true. The faith-based thinker and the reason and evidence-based thinker use very different methods for processing information and deciding what is true about the world.
Actually, spending time with theists is pretty validating of their choice for most atheists. Why would anybody want to be in the theist's place if he can thrive without religious encumberments? Why would an atheist want to be a person who needed comforting from religion? Growing up without religion forces one to grapple with issues that are eventually resolved with acceptance - acceptance that consciousness may end at death, acceptance that we are not watched over or protected from on high, the ability to grieve without false beliefs about seeing loved ones again some day, the acceptance that man is the measure of what is moral, etc..
But if you never get the opportunity to develop those skills because of religious beliefs, then you will need that religion to comfort your fears. As I posted here recently, religion offers no positive purpose or value to the person whose emotional, intellectual, spiritual, and moral needs can be met without it. The fact that a god belief makes a person feel more complete is not necessarily a good thing. Benefiting from a prosthetic leg is great if you have lost a leg, but isn't it better not to need one?
