Re: Not the first piece of absurd preaching to come from the SQLite team
To be fair here I have of agree with the "threads are evil" thing. Trying to debug code that lacks repeatability due to some thread interaction that is not deterministic (due to variable run-time timing, or due to an asynchronous event) is definitely the Devil's work. Yes, there are synchronisation primitives to (hopefully) work around it, but then you get in to the OS war zone.
Stick to multiple single-thread processes where possible...at least such a process can be expected to behave the same for the same inputs, and if not that alone is a bug.