Not really a valid comparison. Most people don't go running around wearing their $500 video card everywhere they go. Flaunting is not owning something, it is showing it off. By the nature of the device, it is visible and goes everywhere the user goes. The user may not be intentionally doing it, but to people around them it may come off that way.
Most people see the value in paying more for a good camera. While there may be value in Google Glass, most people don't see it. As such, they see the device as frivolous. It may be worth that much, or even more, but they don't recognize it. People understand "saving up" for a good camera. I have yet to hear of anyone saving up for Google Glass.
Additionally, someone who can't afford your expensive camera can opt for a cheaper version of similar technology. In the case of the Glass, if you can't afford it (or are not "invited" to purchase it) you can't just buy a cheaper version of something similar. Once other similar cheaper products are available a lot of the stigma will
While for a lot of people, the issue is the potential for recording secretly (though most of that is just not understanding what the product is primarily for), I believe (opinion) for many people that is just the convenient excuse they give so that they don't come off petty.