Clearly, these happy fellows are neither grizzled nor veterans, but they do appear to be non-Japanese.
Technically, I should be a "grizzled Japan vet", but I'm only so chronologically and in terms of sheer volume of experience. The "grizzled vets" of whom I speak are the people who have spent a fair amount of time here (often more than 10 years), who think they now know it "all". They are bored by anything other experienced foreigners have to say because they feel they've already been through it all and there is nothing to learn from the opinions and experiences of others. They are also bored by the experiences of newcomers because they believe they have experienced all Japan has to offer and find nothing of value in the excitement over tourist areas, Engrish T-shirts, food, or whatever the "n00bs" are getting worked up about. Many of these grizzled vets exist in Japan in a rut and have stopped really learning, growing, or actively experiencing life here. They are bored by everything not because there is nothing interesting around them, but because they have stopped paying attention.
When you think you already know it all and have seen it all, you have nothing new to share with others nor the potential to engage in active discussions of various viewpoints. Subsequently, these perpetually bored grizzled Japan vets are boring and I won't miss them.