Sometimes apologists and especially creationists use the silliest of arguments against evolution. One of the silliest ones is the classical "if evolution were true, then it would make it ok to kill the weak and it would justify eugenics."
This is exactly as silly as saying something like "if gravity were true, then it would make it ok to push people off of cliffs" or "if fire were indeed that hot, it would make it ok to burn people with it."
Just because a natural phenomenon happens, or has happened, in a certain way, in no way dictates how we should behave. Natural phenomena do not dictate our morals. In fact, much of our cultural evolution has been all about fighting against normal, "natural" events and conquer them.
There's nothing in nature "guiding" us to do anything in a certain way, nor are we "meant to do" anything in particular. We decide how we deal with our reality as we see fit. If we decide that we should not kill people but instead we should take care of each other, no matter how weak or crippled we are, that's what we can and should do. Our evolutionary history does not dictate any of this. Evolution, and physics in general, is just a completely mindless "automatic" process with no purpose, intent or any kind of "higher meaning" behind it. It just happens. We can make of it whatever we can and want.
Some people who accept evolution are nevertheless quite deluded about it. They often argue how we are "meant to do" this or that because of evolution (or because of whatever natural phenomenon.) Or conversely, how we are "not meant to do" whatever.
Again, this is completely silly. Evolution doesn't "mean" us to do anything. It's just a bunch of natural laws acting on matter and energy. It has no purpose or goal, it just happens. We can do whatever we want with it.
The instinct that many people have that attributes some kind of meaning or intent behind natural phenomena is actually quite deeply ingrained and most probably (and perhaps a bit ironically) a result of our evolutionary past. It's closely related to the concept that there's consciousness behind every phenomenon (which is were the old concepts of there being a "god" for every possible thing comes from.)
Back in the distant past if you saw for example some tall grass moving, it would have been more advantageous for your survival to assume that there was a sentient being (eg. a lion) moving the grass than to think that it was something completely inert (eg. just the wind.) If you assumed that it was a lion, you would flee and have a higher chance of survival. Therefore those whose instinct was to attribute all such phenomena to sentience were naturally selected over those who instinctively did not.
I think this is the root where this whole "we are meant or not meant to do" this or that comes from. We attribute meaning, purpose and sentience to things that have nothing of it.