The author sadly throws Seligman under the bus by comparing him to the quack author of "The Secret". Seligman's work is more than just "Pessimism should be avoided", and he didn't say avoid negative feelings, but that there are 2 ways of seeing setbacks; the pessimist usually thinks it's permanent ("it will be bad forever"), pervasive ("everything is fucked") and personal ("it's because of me"). Meanwhile the optimist would see a problem as temporary, specific ("We just need to fix this thing") and not due to the self, but more to do with circumstances (e.g. "I didn't sleep well so I didn't perform that well").

So it's not about how to avoid acknowledging problems, it's about how you shape your mind to see and deal with problems...