Nobody knows that you are investing. Rich people are always looking to increase their wealth and are looking for convincing reasons for that.
They will use Bitcoin when they feel they are making enough money. They may not announce their investment because many governments may ask them for more fees or some technical complications.
rich people will sell them coins when country ban bitcoin
We really can't blame people even they are rich or not they can accumalate more as long as they wanted, they can post or retweet it whenever they wanted it is up to them , the reason why crypto is being banned because of the government itself, they are too afraid of innovations they think that technology is a threat to the states even though it can help in the economy, rich people help us to reach more people in the other part of the country by using their tweets if they want to announce that they bought tons of bitcoin, we don't need to blame others.