Interesting viewpoint and an informed speaker.

However debt-GDP ratios can not be looked in isolation.

Borrowings used to purchase infrastructure that provides future benefits -- could be reasonable IF the intention was to generate sufficient funds to retire the debt at the end of the respective useful life of the infrastructure asset.

However borrowing to finance operational costs (deficits) today - generate an intergenerational transfer of the bill to future generations.  

It is easy to run up the government's debt on operational charges.  The government of the day is likely to be popular (the joys of the free lunch)

However, the running up of the credit card can impact the government's debt rating.  Credit downgrades increase future borrowing costs.   Also, while interest rates are low now, when that debt comes due, interest rates will probably rise.