Yes the button introduced to stop spam in the blockchain.But i saw in some of my fellow dtubers post was downvoted without any reasons by one of the negatively reputed bot.Even i saw that same thing in other community also.I didnt found any clue whatsoever.Even i also asked some of them.Their reply was like that..."You can not do anything about it cause its decentralised."
I dont know whats the cause but its really happening.