Yes I did say about stress and fighting and the likelihood of one of them killing the other. Sadly the person was insistent that the hamsters loved each other and that her hamsters must be different because she hadn't seen them fight and that. She said that if they did fight then she might consider separating them but that she'd be sad letting them live alone.
I tried insisting that they really really shouldn't be together and that they would probably be much happier alone and all of that but she didn't reply again so I'm guessing she will just ignore me
Edit:
I checked the users reddit and they psoted another photo of the two hamsters together. I have left another message (regrettably it's a little snappy but I just can't believe she isn't listening!).