What will happened to those who use the mixer previously. Is there a chance that my Bitcoin will be connected by Bitcoin use from money laundering or we are still safe? I use Chipmixer every week to mix my coins. Its sad to read this bad news. 
Agreed. This is very much similar to how the government has arrested Tornado Cash's developer for creating a tool to protect someone's anonymity and privacy. I reckon if a car was used by a criminal to kidnap someone, the government cannot arrest the car company or if a cellphone was used as detonator for a car bomb that killed hundreds of people, the government cannot arrest the cellphone company.
And yet, in the case of Tornado Cash, hundreds of millions worth of different coins linked to the mixer in one way or another were frozen. This was generally a blanket move. This wasn't just done selectively to suspicious wallets and addresses. This included funds of innocent and unsuspecting Tornado Cash users.
However, the argument remains the same. The government does not have the right to arrest the creator of the knife if his creation was used to murder someone. I am shaking my head why there are some people who argue that the arrest and detention is acceptable because it is not.