What do you think is/are the reasons why the two of the world's most richest men doesn't support and is against Bitcoin and Cryptocurrency?
There is nothing to think about them. they have been comfort in their 'comfort zone' being super rich on their royalties. I don't know if they really against bitcoin and crypto-currencies, but bitcoin has grew without their support. or might be they are afraid of blockchain as the leading technology which perhaps outdoes their giant corporations.