Non-lawyer elected officials, actually.
Lawyers are just charged with knowing enough of the mess to be able to advise people - but don't shoot the messenger.
The criminal system is also deliberately adversarial, something lawyers didn't make up either.
The civil system is not, at least.
What do you base this on? It depends on the year but Congress is usually 30-50% lawyers.
A lot of legislative drafting is carried out by lawyers in the Legislative Counsel (of the House of Reps, of California, etc.), anyway.
Unless you mean these rules were written before the Bar associations were a thing
Those that aren't are from very close to founding, done in conventions that were mostly not lawyers :)
These are mostly not modern doctrines created by Congress.