It seems to me that steem is a classic scamcoin, and steemit is being astroturfed like crazy. However, if a steemit link contains substantial, on-topic content, then the shadyness of steem/steemit doesn't warrant removing the link.

But if people are posting low-content steemit links in low-content posts, or posting steemit links constantly, then this should be reported. (Note that we might give a little extra leeway for steemit posts in the steem/steemit threads.)