Note that with a goal to eliminate a species completely, the longer you wait to get experience and perfected technology, the better.
A major screw up in such a case would be some random factor, mutation etc. preventing us from wiping all mosquitoes, and leaving a group that would be resistant to current gene-drive technology.
I don't know enough about gene-drives to suggest how it might happen - but the point is that there are always "unknown unknowns".
That smaller group would then quickly spread and replace the previous population, and would be harder to deal with.
Repeat a few times, and you have gradually nudged the population of mosquitoes to be resistant to our attempts to eliminate it.
It's possible that waiting longer and using a better technology in the first strike, would have solved the problem cleanly.
I remember having a similar discussion about HIV and anti-retroviral drugs.
In short, it's an easy position to take if you and the people you care about aren't currently in the firing line and making policy choices on assumptions about future discoveries that we can't guarantee is ethically problematic.
“In 2015, there were roughly 214 million malaria cases and an estimated 438 000 malaria deaths.” While we don’t know how many humans malaria has killed, an estimate of half of everyone who has ever died isn’t absurd. Because few people in rich countries get malaria, pharmaceutical companies put relatively few resources into combating it.
The best way to eliminate malaria is probably to use gene drives to completely eradicate the species of mosquitoes that bite humans, but until recently rich countries haven’t been motivated to such xenocide. The Zika virus, which is in mosquitoes in the United States, provides effective altruists with an opportunity to advocate for exterminating all species of mosquitoes that spread disease to humans because the horrifying and disgusting pictures of babies with Zika might make the American public receptive to our arguments. A leading short-term goal of effective altruists, I propose, should be advocating for mosquito eradication in the short window before rich people get acclimated to pictures of Zika babies.
Personally, I have (unsuccessfully) pitched articles on mosquito eradication to two magazines and (with a bit more success) emailed someone who knows someone who knows someone in the Trump campaign to attempt to get the candidate to come out in favor of mosquito eradication. What have you done? Given the enormous harm mosquitoes inflict on mankind, doing just a little (such as writing a blog post) could have a high expected payoff.