Ummm... I'm no christian buuuut I'm not sure that OP's supposition is true...
Assuming it is though; If there are no repercussions to an action that one enjoys they'll likely keep doing it. Same goes if those repercussions are canceled out constantly. IF Jesus was to command that all sins are to be forgiven (by whom? god? himself? other people?) it would lead one to believe that people might think it's fine to sin. Unless in the process of their forgiveness they legitimately learn that the sin they committed was unjust.
But, I don't think the bible actually endorses disingenuous repentance. And I think even god would have limits for his forgiveness. We might need to have some actual Christians well versed in the scriptures to weight in and confirm that.
Biblical repentance isn't 'sorry'. That would be attributed to "remorse" in both Jewish and Christian understanding.
Remorse is either feeling bad that you got caught, feeling embarrassed and ashamed, and saying "sorry" (e.g. Saul from OT) Repentance is doing things that are different, turning away from the sinful activity, etc. (e.g. People of Nineveh)
I must admit I'm not totally sure where you are coming from (if you mean "confession" as it applies to catholicism or confession as a general relational practice... etc.) But I can tell you from my personal experience that my confessions of wrong doing to others help to heal my relationships (giving validation and acknowledgement to the offended), helping reconciliation occur. Of course, it can't stop there, right? If I say outloud "I'm sorry, that was wrong" I may validate for my friend that she was really wronged, but If I don't do anything about it, then she'll just get hurt again, and this would reveal my lack of desire to change. [there are exceptions of course - i.e. am i suffering from addiction? mind is not well?]
Also, confession seems to help my own walk. Once I "put it out there", its a lot harder to hide from my own shortcomings and mistakes. Its like shining a light in the corners of the basement. I have to admit to myself that scary monster is in that corner.