If you don’t question the Church’s authority then what is the problem with annulments and legitimacy? Not being snarky, if we were talking that would be said in a questioning tone
The Church extensively investigates marriages to determine if the couple properly entered into a valid marriage when they spoke their vows. If an annulment is granted it is because the Church tribunals (each case is reviewed by two separate tribunals) determined the marriage was not valid. Once a marriage is declared invalid, both parties are free to marry if they wish.
As someone in the process of an annulment I can assure you the Church will get all of the painful details. The questions asked are quite extensive. Everything from parents and familial relationships to early childhood to the courtship of the couple to the reasons for marriage to the behaviors of each during marriage including in bed and on and on.
My annulment application was 19 pages when I printed it out to submit to my priest for review and forwarding to the tribunal. Would probably have been 40+ pages had I opted to hand write.
In addition, I had to provide the names and contact info for no less than 5 witnesses who knew both myself and my former spouse before and during the early part of our marriage that they will send questionnaires to and possibly interview by phone. My ex wil alos be contacted the same way as the witnesses to give his view.
I was also asked to submit any psychological counseling records pertaining to the marriage as well as any arrest records, police reports, paperwork from child support agencies and so on.
And I may be asked to have a psychological evaluation done.
As an add-on to all of the above, they Church may decide to restrict me from marrying within the Church for a period of time if they believe that I have unresolved issues that would prevent me from validly re-marrying. If I were to be restricted from re-marrying, I would not be able to re-marry in the Church without proving to the tribunal my issue was resolved and I can validly contract a marriage.
The Catholic church takes marriage and annulment very seriously and they do not use their authority to loose or bind without making sure that they are making the correct decision according to Church law.
The Church is also very clear that children born of annulled marriages are NOT illegitimate.