That’s a statement of statistical fact, though not technical fact. Technically there’s a few. But given that there’s not even 300k tenured academics out of nearly 2 million “post-secondary teachers”, and given that conservative ones are not much above 5% nationwide (tenured or not), in a very real sense they don’t exist. A few thousand professors is negligible. At a very generous 10% of tenured academics, conservatives would represent perhaps 1/50 academics total, and the numbers are worse than that, increasingly close to 1/100 academics total.
But just like with liberals, they wield massive influence on conservative thought despite being almost, in a way, imaginary and fictional.