The most likely answer is profits, for obvious reasons.

I believe that there are a good chunk of millionaires and billionaires who are already in possession of a considerable sum of bitcoin, though are being discreet about it or are just outright denying it since they haven't accumulated enough yet. As an investor, you don't want to compromise your position very early on in the game if you want to maximize your profits, so it is just smart for them to badmouth bitcoin and crypto very early on while buying in the shadows.

Just look on how much gains bitcoin has had within the past 5 years alone. If that isn't enough to tell you that there's money to be made on a 'new internet fad' then I don't know what will. They have their eyes on this one and possibly even cashed out on 2017 and are just doing it more publicly to subtly tell people to buy it since they are on it.