It's simply the result of the US system of education since the 1950s.
Remember there is no universal standard for what gets taught in US schools and there is almost universal acceptance of Alternative Education. Control of what is taught in the US Public Schools Systems are controlled at the very local level. Not simply State or County or even City level but at the individual district level.
And there is absolutely no universal or uniform control of what is taught in the Avoidance Schools or Home Schools or Church Affiliated Schools. What has happened is that Alternative Accreditation groups that can approve almost and curricula.
Sometimes I wonder if there are two types of conspiracy theory believers, or only one type. If there's two types then one type actually believes the conspiracy theories, while the other type knows they're total bullshit but acting like they believe them serves their purposes.
Again, that is a defining characteristic of the Christian Cult of Willful Ignorance and Deceit.
I have absolutely no doubt that the vast majority of Christian Apologists understand that when they are marketing is total bullshit and that the vast majority of their followers actually believes the bullshit.
Could a killer virus be created in a lab and then released in public intentionally or accidentally?
Yup. Sure can.
Did Covid-19 originate in an intentional or accidental lab leak?
The important data is that it was recognized and vaccines and procedures and medicines to address the effects of Covid-19 were created in labs and then released to the public and such research and development continues.
The original source might be relevant if civil suits for damages or criminal charges were to be laid but in this case neither is even remotely possible.