It doesn't matter anymore if you believe them or not bc even if there where people involved that used that moment to obtain large amounts of dash they have had so many moment to sell already.
When you have large amounts and don't believe in a projects you will sell in volume. Dash is a old crypto which had many peak moments with volume before the 2017 bubble occurred and before people could even have imagined a rally like we have seen last year. There where plenty of moments for them to sell long before the 2017 bubble.
The wales that stayed obviously saw something in dash otherwise you wont hold for years if there where plenty of moments where you could have sold with big profits. You dont hold a coin you dont believe in with uncertainty that your bag becomes worthless.
There are plenty of coins who have large whales due buying large amounts with discounts in icos which we seen last year or due to large mining power or some other reason. Even in btc there a major whales and they are doing fine besides some market manipulation where you still cant get around of in crypto.
The people that are still involved with dash after all these years have the best interest for dash otherwise you wont spend so much time and energy in it if there have been plenty of moments where you could have sold and moved on already.