Some people probably dumped because the development team looks young. It could just be 2 people doing everything vs a team. As for the linked in profiles. They are probably new because the younger generation all uses facebook. Hell I'm in my 30's and just created a linked in profile for the first time. It's just like the job market... Everyone wants people with minimum 5-10 years experience. Well you are not going to have that fresh out of college. I would focus less on their age and more about the product they deliver.
I agree, young industry and young people is a plus and not a negative. These guys delivered what they promised so far and their foundation looks good.
Feel for genuine now by taking their faces public.