Khatru, whilst the drink-drive legislation is aimed at everyone, it only impacts those who drink and drive.
That seems a tad simplistic: this legislation impacts on all drivers in terms of their potential behaviour in knowing that they risking personal sanction and the safety of others. In fact, since the limits are lower here in Scotland compared to the rest of the UK drivers here have even less discretion over drinking and driving than elsewhere in the UK.
However, in terms of personal compliance with the regulations this is a self-selecting sample, where only those who intend to drive and consume alcohol are bound by this regulation: non-drivers and teetotal drivers are in that sense unaffected but the wider population also has a vested interest in this issue since we are all potentially at risk of those who drive under the influence.
So, on the basis of your earlier post in which you said 'The advice and guidance on how to live as a Christian, is only relevant to those who have chosen to join the church universal' then drink driving is a poor comparison since it does potentially impact on everyone whereas, as you say yourself, any imperatives contained in Christian dogma alone apply only to card-carrying Christians.
Similarly, the requirement for teachers and doctors in the UK to register with their respective General Teaching/Medical Council applies to the teaching/medical professions alone but is a national law which technically applies to everyone.
Which means it differs from what you have said about the scope of Christian 'advice and guidance' which doesn't apply to everyone.
The same applies to the teachings in the epistles. The epistles were written to Christians in various churches across the Mediterranean area, and deal with issues that concerned the members of those churches. The fact that the foundation on which Christianity exists is open to the whole of humanity means that - once someone joins 'church' - they come under the 'rules and regs' of that body in exactly the same way that anyone joining this board will not have been required to abide by the board's rules and regs before joining, but will be after joining.
So, therefore, these 'rules and regs' aren't binding on the 'whole of humanity' are they?
There is no contradiction, unless you are suggesting that we are all bound by every rule and reg that exists, even if we aren't involved in the life of many of the organisations/societies/nations/people groups to which each of them apply.
I suspect the issue you are implying but not addressing here is that in by saying Christianity 'is open to the whole of humanity', which is a ridiculously grandiose claim, you are suggesting that specific Christian imperatives should apply to all of humanity by default in that Christians, based on what you say, see all of humanity as being potential Christians - would that reflect your view?