I have decided that I love 6A/LJ, precisely because of this. Not that they deleted some 500-odd journals, not because they messed up, but their lack of professionality.
A more 'professional' organisation probably wouldn't have messed up this badly -- because they thought every scenario through, and will have protocols in place to deal with this thing. Not LJ, they are more of a happy-go-lucky disorganised bunch who make up stuff as they go along. Which means they mess up. But it also means that they have the flexibility to improve themselves, and they constantly keep tinkering with the site to add features and make it better.
Suppose Blogger messed up. Do you think the CEO of Google would admit to that, and apologize, in a written statement on the friggin' homepage? I don't think that would happen. And yet the CEO of 6A did just that. That takes guts - and I appreciate that 6A and LJ have those guts.
That being said, trust is good, but control is better. So if you want to back your Journal up, I will direct you to LJArchive. Downloads entries and comments, and has a really handy search function.