Lots of people saying it's symptomatic of everything that's wrong with casual gaming, ad-supported gaming, and general timewasting.

I have the impression the author saw it as a marker on the path to making more high quality games, and is horrified by the idea of becoming the CEO of Flappy Bird Inc., much as the creators of novelty songs that become one-hit wonders end up being permanently associated with something stupid that was done for a joke and/or a quick buck.

Also, I see a significant social stigma in Vietnam to exploiting 'that stupid game my kid is wasting all his time on.'

Every creator gets harassed these days, to varying degrees. You can create the most sublime and enthralling game in history and people will still complain about it. It's even worse if you create a simple game that is frustratingly difficult. The culture of entitlement and harassment is one of the worst aspects of the internet today.

He got harassed because the game looks like it didn't take much work, and it's more popular than people think it deserves to be.