That disclaimer doesn't mean shit. Nice try at gaslighting though.
The disclaimer means that VAERS data does not substantiate your "18000+ recorded deaths" statement. Referring to VAERS as the source of such claim is a blatant lie.
How does that unsubstantiate the claim, I don't see any numbers of deaths in that statement?
The entire thing is one big CYA essentially saying the data may or may not be valid. If anything, that statement confirms his claim that the data contained in VAERS is underreported.