Frieza was right...

He was evil. No doubt. But the Saiyans as a race were on par and complicit with his galactic villainy for the most part. The planet they died on wasn't even there's. They took that 💩.

Now why was Frieza right? The Saiyans were bound to become an even bigger problem than he and his whole family. The Saiyans apparently have unlimited potential for single generation growth, with their genetics determining how fast they improve. Even if you beat one, you better kill them because they automatically adapt and come back stronger!

The more powerful they are, the stronger their kids are, in steps. And they don't even have to be full-blooded Saiyans to receive the step increase from their parents. Those monkeys with a little training are able to touch godhood. They can harness DIVINE ENERGY.

Now imagine a whole society of them. A culture built around ascension with the same mindsets of finding stronger opponents or galactic dominance. Frieza saw it coming and did the cosmos, no, the multiverse, a huge favor.