something deleting comments on some forums

Both tha me and Robbo have had our comments deleted on two Posts and some of Robbos posts that he started  have been deleated aswell. 

Heres one of the posts we commented on that has been deleted

  

On here I had sent a message as a reply 

And then I sent a reply to the last message later on and Robbo also replied to the last message from this  post. 

Theres also another forum where  Robbos message have been deleated and I sent a message and someone deleated that one aswell. 

is anyone else haveimg this problem apart from me and Robbo 

and if so why do you think it is happening and why do you think is doing it? 

Do you think its a moderator doing it, or do you think it’s something else?