I don't know what is controversial about that statement if you put it into pg's context. Anyone complaining about it surely could do something more productive with their time.
The reaction is not directed towards business plans or whether PG has even read one or not (hint: no one cares). It is about his consistently proven proclivity to say edgy, inaccurate things, often which add 0 value. Then get upset that people are pointing this out on twitter. It's pretty annoying that he acts this way on twitter considering his previous essays have been ogod.