It seems so obvious. The examples below are not directly related to the Crispr genetic manipulation cases, but they highlight the same problems...
It turns out that the cystic fibrosis that the people wanted to eliminate had been selected for during medieval times and made people immune to yersinia pestis (the cause of bubonic plague). Without that gene (which usually does not manifest with full lethal penetrance), our world population would be vulnerable to a super plaque even today should yersinia develop resistance to present treatments (which usually happens with widespread use of meds).
It turns out Sickle Cell Anemia Gene proffered resistance to malaria in Northern Africa, and again, the less severe manifestations of SSA are much more common. Thus again, there has been a natural development of genetic traits and diversity to protect mankind from a vulnerability, and there were scientists who wished to eradicate that diversity. Vulnerability lies in homogeneity.
There are multiple examples in man made attempts at introduction of invasive species where the introduced species caused more problems than the problem it was meant to solve, and that “problem” species turned out to have unknown roles.
Thus, my points:
1) It is the ultimate in human hubris to assume that we have all knowledge and information at this time to be able to safely make the determination that eliminating such a fundamental aspect of nature will not have other far reaching consequences.
God doesn’t make junk. Even mosquitoes have roles, and it might be more than the critical natural population control issue. And there are other species population control and roles that the mosquitoes play with them., and being a basic part of the food chain, etc..
2). The weaponization potential for Crispr is terrifying, and it’s coming whether we want it or not because it’s so simple that a college kid with a basic lab could do it with a little online study.