ourmine doesn't do anything malicious, and is, as far as i know, completely harmless. they do this quite a bit, mostly only gets reported if its a celebrity or big company tho. all they do is gain access to whatever website/database/account they were able to break into, and then do something like this, send out an email to users that could be harmed, and post a public announcement on their front page/account. they never change passwords or do anything (that ive heard of at least) with the information they potentially have access too
p sure their motive is just to promote password security, only time ive heard of them having any other reasoning was when they hacked the account of one of the pokemon go developers because they hadnt released the game in south american companies or some stuff