What advantage have western powers gained from their “assassination” of Putin’s enemies?

Someone who is like Skripal? Who has been released by Putin's government in exchange for Russian spies in the UK? Let's just say no one would have known who that guy (Skripal) even was if not for his attempted assassination. He was of absolutely no value to Putin. Again, they released him after he served time for spying for Britain! But to have him poison, right before Russia is about to host the World Cup? Right as the US and the West are trying to frame Syria's Assad as a mass killer, and Russia acting like Assad by brazenly executing people on the Western soil? Plenty of advantages. Make Russia an axis of evil.

Btw, such a frame of mind allows the CIA and other Western Intels to act with impunity. Would anyone in the West be outraged, if, for instance, a pro-Putin, Russian spy was assassinated in cold blood? Or what if the CIA hacked into Russian network wreaking havoc on their government systems? Perhaps even took out Russia's internet for a day? Framing Russia as evil plays very well into the hands of everyone who wants to attack Russia with impunity.

Remember when the US attacked Saddam Hussein in 1991? One of the main issues, was the incubators that the Iraqi soldiers allegedly destroyed by killing the babies. This was used by George HW Bush in part to justify US military action. Those incubator claims were false, but it didn't matter after the US was done bombing Iraq.

In 2003, there were Iraqi WMDs' It doesn't matter they weren't found.

This is just geopolitics 101.