Feeling nostalgic for a time which you didn't experience. Nostalgiosity is a combination of the words "Nostalgia" and "Curiosity". It is used in contexts where you would be nostalgic but it is logically impossible for you to be because you were simply not there. Your feeling of nostalgia is therefore not real, and is more similar to curiosity. What you are are actually feeling is a kind of curious nostalgia, nostalgiosity.
Nostalgiosity is by definition only experienced by the younger generation. In general, their views are do not represent accurately the times which they are referring to, and often times the things they feel nostalgiostic about are simply wrong. Hence, nostalgiosity is a very generation specific feeling that relates to how the olden times must "appear" to the newer generation. Nostalgiosity about a specific time cannot be felt by the original generation.
"I am experiencing nostalgiosity for the 60s. Those were great times. All that revolution, freedom, love. It must have been wonderful to listen to Bob Dylan while singing along with others barefoot in the grass, trying to tame the long hair you took so much care to grow."
"Wow I wish I grew up in the middle ages. Then I would be knight and I would be chivalrous, and I would yearn for my pricness and fight in jousting matches for her. Those must have been heroic times"
"I'm feeling nostalgiostic for the early days of video games. I would have loved to be hacking pong machines, and taming space invaders on the Atari. Or putting together scrap metal to make arcade games. Wow, those were the times."