Also, nowhere in the article it says that Russian security forces ended up killing rioters.
What really happened is that Kazakh military did not want to obey the President orders when this chaos started. It's speculated that this was act of treason by some high officials in an attempt of coup. That's why Tokaev asked Russia to intervene. After Russia confirmed that they actually do support Tokaev with some symbolic forces sent, Kazakh military started to obey the orders and started to actually do what they must. That's my opinion.