But if Steem decided to ban this by definition, started removing or blocking posts like that, or having official committees deciding what goes and what doesn't, I would be very alarmed.

So would I. If Steem ever acquires a committee able to block posts, I'll be gone. My post was only meant to counteract Hive account@jonnybitcoin's post and raise the issue of a clear conflict of interest taking place.

Also, I wanted to prevent this perception from spreading:

Steem is used by BitShares shareholders to acquire new investors and then use their capital to salvage their own failed BitShares investment.

It's completely untrue (and I don't think BitShares is a failed investment) but we need to be aware that perception is not a rational beast - it just needs one small incident to be able to flourish.