I agree with your assessment of what a code of conduct is.
That said, just the 'code' is pretty useless without a process to give it life. This is exactly like laws that tell you what you can and cannot do, and the process tells you how you evaluate whether or not the laws have been broken.
So on the one hand you have a document that says, if you're part of this community you will be expected to do this, this, and this other thing. And then this process side is "if you don't, these are the consequences; further this is how we will evaluate whether you haven't followed this code ..."
> From a practical standpoint, due process can be
> simple as the people assigned to deal with
> complaints saying, "This is problematic. Please
> stop."
I see it differently, practical or not, the reason behind having a process that
requires disclosing who made the accusation of failing to follow the process, and the evidence that such a failure occurred, and a rebuttal from the accused, puts the transgression into
context for all parties so that a fair judgement can be made. In the absence of an investigating body it is the only way something can possibly be fair.
From the practical stand point the process can be as simple as the adjudicating group sending an email to the accused saying "Bob has accused you of violating our code of conduct, and offers as evidence the following; ... what do you say?" [2] There isn't any need for actual lawyers and you don't even need an appeal process. Once the adjudicating body has made its decision on whether or not there was a violation then they can enact what ever remedy is specified in the code of conduct.
In your example, the only way "people assigned to deal with complaints" could say "this is problematic, please stop." is if they take on the role of the accuser. And if they do take on that role they must only do so when they have direct, and for them incontrovertible, evidence of the violation, rather than hearsay from someone that there was a violation.
I feel it is important to understand why the process has to be at least this thorough because it prevents abuse and injustice. One of the most interesting things about the law for me is how it creates these sorts of processes to deal with the fact that people who have to run them may be bad actors. And then still generate fair results[3].
[1] Initially only to the adjudicating authority, the accused and the accuser.
[2] And of course the adjudicating body has the obligation to do everything in their power to corroborate the evidence presented and the rebuttal.
[3] In the absence of grand collusion between accuser and adjudicating body.
