That's not the phrase we're talking about. What is dishonest is their reason why they are disclosing the method to paying customers but not the general public, which is simply that they "are too busy". They're too busy to demonstrate the method once to everyone but have plenty of time to demonstrate it over and over again to their clients? That can't be true because it simply doesn't make any sense.
If they just straight up said they're not willing to disclose it because it is their trade secret then that would seem perfectly logical and honest to me.