there is one thing that both parties increasingly seem to agree on: You should work longer.
Klein's thinking is that people do not want to work longer, so raising the Social Security "retirement age" is a bad idea. His conclusion does not follow from his premise. To avoid this sort of error, we need to stop using the term "retirement age" to refer to the age at which one becomes eligible for government benefits.
Instead, think of it as the age of government dependency. If Klein does not think we should increase that along with longevity, then he is arguing that as lives get longer and longer, taxes on working-age citizens should get higher and higher.
Keeping the age of eligibility low may not necessarily help people to retire sooner. It may have the opposite effect. By keeping taxes high, it may reduce employment and wages for people of working age, thus making it harder for them to retire when they would like.