You need the "the" in both. Also, you should use "that" in both.
- The results speak to the organization the infrastructure lacks.
First off, this needs the "the" before organization. This is referring to a specific thing that the infrastructure lacks and needs the definite article ("the") there.
An important note: this should have a "that" after organization. This makes the sentence structure a lot clearer, according to my instincts in native American English. Without it, it looks a lot like two sentences you forgot to put a period between. Thus, the correct version of the sentence would be:
The results speak to the organization that the infrastructure lacks.
On to the second sentence:
- The results speak to the lack of organization the infrastructure has.
This also needs the definite article. It's basically the same sentence with a different verb and "lack of" added, and follows the same reasoning. It also needs a "that", and, if you want this same exact wording (which I don't really recommend), the correct version would be:
The results speak to the lack of organization that the infrastructure has.
What I really recommend that has the exact same meaning would be:
The results speak to the infrastructure's lack of organization.