There really is no justifiable reason to support steem or blurt or even post on them really.
Steem is centralized and has no developemt and is like earning a wage but your boss keeps your wallet and can do whatever the hell he likes with it. i.e centralized and easy to manipulate the chain.
Blurt removed downvoting and the DHF iirc and also completely ditched hivemind settling for hiveD handling all api requests.. which will never scale, not that they'll ever grow to a size that needs decent hardware and it's also completely worthless.
Hives the only thing that's been progressing. Sure it's got many problems that are not really blockchain related but societal and educational issues, as well as many frontend issues and user experience issues but at least we are moving forward.
Acrivity ist not moving forward, i wrote a post about it yesterday.