Hi, I think there is a misunderstanding somewhere here

I think what your friend should have told you is that the free blog services do not guarantee the safety of your blog & therefore if the service you were using was to be hacked, you could well lose your blog & you cannot hold the free service resposible for any loss!

This is one of the main reasons why any serious blogger usually opts for self / paid hosting, as you have far more control over the hard work you have put into your blog.