Appeal to consequences.

The basic form is:

If x is true, then y (positive consequence) will happen. X must be true.

or

If x is true, then y (negative consequence) will happen. X is not true.

Clearly, this type of argument is erroneous. It is akin to saying “It would make me happy if I were the King of France. I am the King of France.” Or, more commonly, “If there is a God, then people will behave morally. There is a God.” Besides the fact that people who believe in a god clearly do not always make better moral choices, the positive outcome of more moral behavior does not prove the truth value of the statement “There is a God.” Just because it would be nice if it were true does not mean that it’s true.

What is often most concerning about this line of thinking is that it shows a cynical disregard for the value of truth, in favor of positive outcomes. A consequentialist ”ends justify the means” type of argument. Now, if the name of the game is just picking what will get the job done, then let’s at least not pretend that we’re talking about truth. Otherwise, your arguments amount to lying in order to get what you want.