"Which proves the point that Adventists don't really know God"

Huh?  You cannot "prove" this generalization from anecdotal evidence.  Anecdotal evidence might "prove" the Existence of some Adventists who do not "really know God".  But the broader assertion regarding Non-existence of any Adventists who "really know God", simply does not follow.

I submit that it is not for us to judge who does or does not "really know God".  Arguably no human today can claim to "really know God" (see Matthew 11:27).