When the subreddits "going dark" episode was happening on Reddit, the admins of /r/suomi (the Finnish-speaking equivalent of /r/finland) decided to keep the subreddit privated for much longer than most others. This may have led to a slightly higher percentage of Finnish users finding a new home here on Lemmy compared to other nationalities.
The reason we use english online so much is because when you search the web for something in finnish your top results will include vauva.fi forums (vauva = baby, used to be a magazine with a forum. Now only the forums persist). You find so much more information searching in english.
To be fair I once got an answer to my question on the baby forums about changing oils in my car from that forum.
I don't think it is. For some reason Finland just seems to be overrepresented online despite its small population which might create such illusion but that has not been my experience on Lemmy. I only remember encountering a handfull of other Finns here.
And judging by instance statistics (at Join-Lemmy for instance), it's Germany where Lemmy is more popular. Discuss.techns.de alone has total 6595 users and 794 monthly users. Sopuli for comparison has currently 4957 total users and 489 monthly users.
The instance user count statistics really don't tell anything. For example, I'm a Finn and I don't speak German at all but still my account is on tchncs.de. This instance is open to everyone, the same way than Sopuli is not just for Finnish-speaking folks.
I guess Finland has a larger non-mainstream community than is normal. However it feels weird that there is such a small Swedish counterpart, since they also have a relatively large pirate movement. Perhaps because the Swedish instances are very political, so Swedish users spread out over the fediverse?