Steem lowering delegated sp??

So i just got a text from a good friend @beavishoek he sends me a screenshot..

being on here three weeks less then me he says wtf does this mean? my sp just tanked he says. i look at mine still the same.

No message sent out no nothing they @steem halves delegation on his account and seems like a multitude of other accounts.

This is a very dick move if you ask me. No warning at all just halving the delegation of someone new who is doing well and enjoying steemit. My delegation stayed at 28.5 but my friend who i got into steem just got a slap in the face... If i was him i would definately be feeling the urge to punch the developers of this platform right in the throat. The real issue i have with this is the lack of reasoning as to why this happened. can anyone explain why that has happened to some but not others?