Other things are also noted that would be considered off topic. Whether the board is free or premium, who the moderators are, when the board was created, these are not about the company, they are about the message board. It's for informational purposes only.
Technically, discussion of boardmarks would be considered off topic. Removal of the posts, therefore, appropriate.
The way I, personally, handle the situation is to step in when boardmarks becomes the topic as opposed to the company. Then the entire thread gets removed including the original that generated the responses.