I am not saying I disagree that this practice is shady, but I am not sure where the bad attitude and grow up part is coming from. There is a lot in between "your practices might be misleading and slightly shady" to "grow up you have an incredibly bad attitude"
A user was asked to endorse people, but that action ended up endorsing a product; that is the very definition of deceptive viral marketing.
Someone who is too eager to attract users and too confident to politely respond to even the most scathing criticism is clearly struggling with a lack of maturity. If this was an overly zealous employee, that would be one thing, but the founder/CEO? Giant red flag.