Evolutionists exclude the origin of life from their theory because it's too difficult for them to overcome. Evolution is largely an extrapolation. We see a micro-organism mutate into a slightly different micro-organism, so we theorize that over time those mutations could produce a giraffe. We see variation within the breeding of dogs, and assume the same type of thing. In both cases it's an extrapolation. But some people will accept the extrapolation because they see the event upon which it is based.
In the case of the emergence of life from its absence, there is no record of any such thing ever occurring, so there's nothing to extrapolate from. So evolutionists have deemed the matter to be outside the scope of their theory, avoiding the problem.
[*** Sigh ***]
It is outside the theory. The theory proposes to explain the variety of life. That's all it does. No one is ducking anything. It's true that the origin of life hasn't been worked out. This is irrelevant to the theory of evolution. The theory works just fine. It explains what it proposes to explain. It doesn't explain what you want explained.
Similarly, no one knows the origin of electrons. But we deal with electricity quite well.