I can imagine a scenario where the testing takes 15 years, and a scenario where the testing is done in 1 year. I think it's probably wrong to look at it purely as "we should wait X years". The author describes the 15 years as "regulatory limbo" implying that it was known as safe before that, but I have no idea whether that's the case.

In general, you have to weigh the irreversible cost of unintended consequences with the irreversible cost of known human death from mosquitoes.