No, but it does include the time to get yourself and your vehicle on to and off of the train that carries vehicles through the Channel Tunnel.
The airlines that redirected flights to Paris arranged buses to London.
An alternative reading to it 'being idiotic' is that it was clearly an exaggeration to prompt some critical thinking about the original claim.
And I can tell you, it might be theoretically in Google Maps land to do the journey in 6 hours, but IRL in this scenario it won't happen. Actual empirical evidence.
Consider the amount of train/ferry transit between London and Paris. That doesn't exist in the US. Rental car companies don't keep that much extra stock on hand, and really do not love renting cars for inter-state one-way journeys.
I categorically reject that getting from Atlanta to London with ATL nonoperational would be either faster or easier than getting from London to Atlanta with LHR nonoperational.