is the result of the effort of a single man who decided to give some productivity to his free time between saying goodbye to his last job and hoping to get the next one.
In search of a proof of concept, did an improvised work along with the name as well.
Then it gained a lot of attention and is now well known as the decentralized version of Youtube and that is why it has that name (where "D" means "decentralized").
RE: DTube Sounds like a Gay Porn Site