I migrated away from Roam because the company treated me poorly when I was a customer of theirs. So this is partly spiteware . Other people want to leave for different reasons; the expense of Roam is one, the necessity of trusting your private thoughts to some random cloud company is another.
Software written in a spirit of revenge. Not to be confused with malware or black-hat hacking tools, of which there are plenty. Spiteware is perfectly functional software but sticks it to somebody. Often an open-source alternative to some commercial product.
The grand-daddy of spiteware is the entire Gnu project. Not to recap that whole history, but Stallman was very hurt by the fact that most of his peers had gone off to a commercial company (Symbolics) and left him behind. The whole Free Software Movement and GNU project stemmed from that hurt.