It has to do with preventing to lose your follows. If you created the new keypair somewhere else Nostur will try to fetch your follow list first before enabling the follow button. If there is no existing follow list or a problem with fetching it, it will stay disabled, follow lists are still tricky on nostr unfortunately.
dude, thanks so much for explaining. that makes sense cuz i also tried creating a keypair in the app instead of importing existing and it worked just fine any idea how/when the client decides to renable the follow button? im still confused why it started working, seemed like it started working when i tried coracle and was able to successfully follow someone on that client and then everything started working on all clients, but im not sure if that was just coincidence.