There's nothing nonsensical about it. That's a very poor analogy as well, comparing a startup's growth to the spread of a highly-infectious virus.
COVID19 spreads by default. If you leave it alone, it will spread uncontrollably. China went from 0 to 79,000 confirmed cases in 2 months, despite running the largest and most extensive quarantine in human history. If there was no quarantine, you could expect truly exponentially higher number of infections.
The problem with these things is, if the rate of spread is >1, then it becomes exponential. That is, if the average person infects more than one person, then the rate of spread is going to get completely out of control. Unless of course, you can impose measures that reduce the rate of spread to below 1.
With coronavirus, it's not possible to do this. The reason is that many people are asymptomatic for weeks, while at the same time passing the virus to other people. If you cannot identify infections before they have the chance to spread at a rate of >1, then the spread of the disease will by default be exponential.
A startup does not grow exponentially by default. Many actions need to be done correctly to continue growing. A business's default state is death.