When you use a company’s security solution, you are placing your reputation in their hands, and you must trust their ability to think through how they maintain security of the information they are managing, as well as the protection their solution is providing to your business directly.
Comodo has an in-house lab to validate the security of files with an unknown security profile and provide a verdict that is then used by all protected systems. We do not share customers files with third parties, because we recognize the implicit risk of sharing binaries with anyone. Comodo has a strict policy where customer binaries and data never leave the Comodo Infrastructure and are analyzed by Comodo-employed experts only.
For a company to use an external third party to analyze unknown files is implicitly(unnecessarily or knowingly) increasing the security risk. To then allow users a choice about how to implement that process raises the security risk even higher which seems unnecessarily irresponsible.
You cannot blame a user for making a choice; the responsibility lies with the vendor.