The term Theorist, by definition, points to someone who is concerned with the theoretical aspects of a subject. Theoretical physicists, for example, are people who study the fundamental laws of physics through abstract and relevant disciplines like mathematics. But the people most call conspiracy theorists fail to apply proper logic to their thinking. Most of the time, in fact, they aren’t thinking at all.
It would also be best to consider the multiple definitions of the word theory as you read this.
In scientific terms, the word implies a robust set of rules and laws that explain a concept directly. The Theory of Relativity, for example, or Gravitational Theory, all contain understandings matching the nature of reality.
For a body of knowledge to be a scientific theory, it requires predictive and explanatory power. The notion that the earth is flat lacks both and is, therefore, not a theory, only a belief similar to a religious doctrine.
“A theory not only explains known facts; it also allows scientists to make predictions of what they should observe if a theory is true. Scientific theories are testable. New evidence should be compatible with a theory. If it isn’t, the theory is refined or rejected. The longer the central elements of a theory hold—the more observations it predicts, the more tests it passes, the more facts it explains—the stronger the theory.”https://www.amnh.org/exhibitions/darwin/evolution-today/what-is-a-theory
The weak or popular definition of the word points to a hunch or an untested guess held by an individual based on their limited observations. It deserves only as much merit as a personal opinion.
Remember that opinions are not facts. And while the humans holding them deserve respect, the merit of that opinion should always relate to the value of the argument and the evidence behind it.
Therefore, according to both definitions of the word, evolution isn’t just a theory, and you should be allowed to throat-punch anyone who says this in defence of their opinion.
The definition of “should” also is contestable here; I do not endorse violence, regardless of how sweetly appealing it might be.
Remember also, that people who push lies and misinformation about the fundamental nature of reality are conspiracy theorists only according to the second definition of the word.
It is critical to understand that most people pushing these hunches are victims of con artists who prey on human biases and fears. These demagogues use scientific terminology and statistical figures to mislead people all the way to the bank. They are no different from the televangelist who sells salvation to needy, credulous humans.
— The Devil Unbound