Actually you do, since you are using it wrong.
Again, why are you so resistant to learning something?
You have a very non-imaginative conception of language. You think there are rules beyond understanding.
An authoritarian nature in regard to language.
Not an understanding.
And this is a common phrase.
Exponentially greater: To be greater in an exponential manner.
It is really no more complicated than that.
That's basically a circular definition, you're not showing that you understand the word.
Exponential refers to something involving exponents, generally a curve. To define a curve you need a number of data points greater than the highest exponent in the equation describing it.
You have only two data points, though--the highest exponent can only be one. An equation with the highest exponent equal to one is describing a straight line.
Now, some uneducated people might be misusing the term but it is misuse.