Cam, you are suffering from an illusion. You seem to think the self-tapping screws are structural, they probably are not. The joint is almost certainly a GLUED JOINT and the screws would have been put in simply because shooting a line of screws in while the glue sets, is cheaper than applying a hundred clamps and then going back to unclamp them afterwards.
This is standard carpentry practice, that's what you do with a big glued joint while the glue it setting up. Removing the screws would leave holes, so they're left in place, even though they serve no purpose after the joint has set up.
Modern adhesives aren't at all the same as the butyl tape that C&C used to caulk their bolted deck seams.