I couldn't disagree more. Chaos is not "good", not even in the slightest bit. Chaos does a really good job of selling itself as being "good", and if not good, "justifiable". But the only motivation for Chaos is to get your soul. If you are useful, it may use your soul to get other souls, but that's it. Everything else is forfeit.
At the same time the Imperium doesn't really provide "safety". Many of the hive worlds function as "freely" as Chaos worlds might, run by gangs, corruption and skullduggery. But as a whole the Imperium does ensure the survival of the human race. Survival is better than not, regardless of the cost. "The dead know only one thing, that it is better to be living."
Regardless of all the nonsense that goes along with being a part of the Imperium, siding with Chaos means that you are no longer siding with the survival of humankind, and that is unquestionably worse. So even though many of the Traitor Primarchs originally thought that Chaos may have provided freedom/usefulness, and that the Imperium and the Emperor were oppressive and overbearing, Chaos kept pulling at them until there was no return. Whether the traitors realized it or not, their motives began to threaten the survival of humankind.
The Thousand Sons are a fine example of what "survival" might mean to Chaos.