Toptobottom. Your logic says that in this case, you must consider the unthinkable. You chose your unthinkable theories with no evidence whatsoever. So let’s show how ridiculous that is. I can offer some theories with real evidence in this situation.
What about Dave having a dashing ‘tash? Maybe he was a secret Village People fan? Maybe he couldn’t cope with being gay?
Dave visited Moscow a few years ago, maybe someone was about to oust him as a spy?
These two scenarios are ridiculous, however they meet your standards of evidence, ie “think the unthinkable”.
Come on man! His family and friends read what is said here. He can’t defend himself. Show at least a little bit of respect........