It seems that the 21st century responsible disclosure procedure goes like that:
0. use tor for the research itself
1. report problems anonymously
2. if they don't care - report them to law enforcement for breach of confidentiality
3. if these don't care either or don't accept anonymous tips - make noise in the media
Of course, this is for dealing with idiots who keep their data on public FTP. If the attack takes some clever hacking, go check if they don't offer bug bounties. Funny times we are living in.