I quibble with the language you use. Evolution does not justify anything. Evolution is a process, a natural process such as the flow of water. So, any species that is not conscious of what it is doing may eliminate or horrify another species to advance its survivability, and no one or nothing will protest. However, we humans are not such. We are conscious. We have the ability to step outside of the process of which we are a part and ask questions about ourselves and the "big picture", much like stepping out of the river to contemplate its course, its use, its value, or its beauty. We are the only species (that I know of) that grants "rights", and we grant them only to ourselves - behavior that further enhances our survivability. I don't think we any longer do so in order to advance our numbers, as we have plenty of numbers now for eons. We do it because as we evolve we can empathize more with other humans and realize they want the same things everywhere; hence, we "grant" all humans the "right" to various life enhancements.

We have, of course, the option to extend these rights to other species as our ability to empathize and relate evolves.

Here's an interesting idea: Many thousands of years ago there were two human strains on the planet - ourselves and the Neanderthals. They were another type of human, an amazing idea to me. Apparently, they were gentle creatures and pretty smart, for the times. We wiped them out. What if they were alive today still? How would we treat them? Perhaps these questions around primates is a way to make amends for past brutalizations.