Mods can deal with controlling members. Thanks for your concern UV but it's unnecessary, it's my job to deal with out of hand posts, not yours :) If you see something that seems over-the-top in the future, feel free to report it instead and the moderator of that section will take care of it!
Do you have to like all the Pokemon games or just the main games? What about the anime or the manga, do have to like them too? Do you have to like every single thing that is Pokemon related?
It just raises too many questions.
Now, granted your talking about people who only like one or two game of the franchise but even then I think it still counts. There still a fan of something Pokemon related and if they liked say over 151 different Pokemon, I think that's enough to count as a fan of them.
For me personally to see someone as a fan of the franchise in general, it's not a high bar. I only expect them to know about new main game releases and give them a fair chance/play them before passing judgment on them. I would like the definition of a 'fan of Pokemon' to change merely for the sake of being able to have a conversation with people. Especially on college campuses, it's common if you sport something from the first generation publicly for a person to come up to you, profess to be a big fan of the franchise, and then immediately backpedal if you ask them about anything more recent than Gen III. I love wearing things related to Pokemon but now I end up just avoiding anything that has Gen I or II Pokemon on it because it's frustrating to deal with time and again getting excited to have a conversation with someone about a subject that I'm passionate about, and realizing that when they said they're a fan they meant that they liked it for a year or two in '99.
There would also be the cutoff of when Pokemon stopped being a 'fad', which is about halfway through the third generation. A majority of people I know that claim to be fans but really just liked it during fad stages like the first two generations and ignored everything after that. If I'm lucky I may run across someone that played Ruby or Sapphire but after that the fad stage was at its end (at least in the US, idk about anywhere else), so anyone that remained interested beyond the third generation would definitely qualify as a 'fan of the franchise'.