You are in error.
I. is not a part of Church law.
I. is a part of church law.
It is not part of the universal laws of the Church as expressed in the 1983 Code. It is, however, proper law in many jurisdictions.
(For the benefit of any reader here who is not aware of the difference between universal and proper law, universal law applies to the whole Church, whereas proper law applies to only a designated part of the Church).
Hence my point stands - the Church is able to require civil divorce as part of the annulment process, and does require it in many situations; ergo it is not a sin in and of itself.
*Can. 1692 §1. Unless other provision is legitimately made in particular places, a decree of the diocesan bishop or a judicial sentence can decide the personal separation of baptized spouses according to the norm of the following canons.
§2. Where an ecclesiastical decision has no civil effects or if a civil sentence is not contrary to divine law, the bishop of the diocese of the residence of the spouses, after having weighed the special circumstances, can grant permission to approach the civil forum.
§3. If a case concerns only the merely civil effects of marriage, the judge, after having observed the prescript of §2, is to try to defer the case to the civil forum from the start.*
The canon says nothing about divorce being sinful. In fact it reinforces that there is a distinction between the civil and sacramental elements of marriage, which was my entire point. The Church recognises this distinction, and thus in many jurisdictions wishes to see a civil separation as evidence (not conclusive, but suggestive) of the non-viability of a marriage prior to considering whether a sacramental bond exists.
Section 2283 states:
If civil divorce remains the only possible way of ensuring certain legal rights, the care of the children, or the protection of inheritance, it can be tolerated and does not constitute a moral offense.
However, I realise that in answering the OP’s question about a civil divorce, I have assumed that all references to divorce in this thread meant a civil divorce, which is probably not the case. Given that the Church recognises civil divorce but does not recognise sacramental divorce (there cannot be a ‘divorce’ of a sacramental marriage, because of course a sacrament persists irrespective of a legal separation), I see that I have confused the issue by not making that distinction, for which I apologise.
My intention was to reassure anyone who has obtained a civil divorce that no sin is intrinsic to that action, in case that misunderstanding might have followed from the discussion thus far. I apologise again for not being more precise in my use of terminology.
In Christ,
Withburga