>>33633615To fit in. In case you didn't know, humans are social creatures. They like getting along with each other. Even if they don't understand the hobby of someone they're interested in, they'll try to be nice about it, to appear interested and to get along. This could also apply to men, but on a smaller scale. Men either tend to be complete betas or too blunt. If they don't like it, they'll either make it clear or just appear disinterested.
That's all really broad categorization, though, and not something you should use as a basis to judge situations in real life. A lot of women that seem like they're faking it often actually do like Pokemon. Sometimes, if someone new is trying to get into it, it might be that they're interested, but a bit confused, so they're not enjoying it to the fullest. Either way, the best thing to do in any of these situations is to honestly ask the other person in the nicest way possible, so they don't feel compelled to lie just for your sake.