Thank you. I feel like people either think "Stalin was a socialist/communist and a horrible leader" or "Stalin was a socialist/communist and good, actually" instead of considering that maybe the socialist branding was just the propaganda they used to justify the dictatorship.

There is also a Swedish stereotype that Finnish people always have knives and that they take them out when they're drunk.

The network effect is one reason, if users are responsible for the content then there will be a shortage of content until enough users join.

Beyond that, humans are social creatures and want to fit in. If your community mainly hangs out on one platform, people will want to be a part of that platform. What helps is if people with a large enough following or entire communities make the decision to change platform, but that can be tricky.