Yes, you should be concerned.
Because cults never disappear due to bans. They empower the hard core members - not only in the banned country but also in other countries.
I think a little differently!
You should not compare reality with the times of Stalin and Hitler. Then there was no information. Today is the internet age. And the JW cult is already breaking! It remains to make adepts think! Stress, prison, arrest - a good atmosphere to turn on the brain!
Therefore, I am not concerned, and much more should not!