I realise reading through Romans 14 and 15 that it is a subtle passage in Paul's thought. It is mainly about a controversy over eating food. But it is not solely about that controversy. In 14:5 Paul notes another controversy, 'Some judge one day to be better than another, while others judge all days to be alike.' (See also Colossians 2:16). Clearly Paul thinks the theology over handling difference is applicable to more than one issue.
Further, Paul is tackling a question of difference among his readers, but he takes pains to point them all to the common ground they share. From 14:5b through 14:9 Paul lays out the common ground they share if they are willing to see it in each other. It has three aspects. First, an individual aspect, 'Let all be fully convinced in their own minds' (14:5b). If we are going to have difference among us, Paul seems to say, the least responsible thing we can each do is check and re-check our thinking so we are convinced we are right. What a waste of time and energy to argue about our differences if we have not yet fully thought through what we are asserting to be vital truth! An observation I make after many years of working on differences over human sexuality is that the process has gotten rid of silly ideas, badly thought through suppositions and ill-considered conceptions from my mind.
Secondly, on all sides of the controversy, people are honouring God. Whatever the presenting differences among Christians, we share common ground over our resolve to honour God by how we live. In respect of present sexuality controversies I offer two observations about what I read on the internet. (1) Often little thought is given to the possibility that those we oppose share with us a desire to honour the Lord. (2) An obvious logical move to make on such a matter is to claim that our opponents are not true Christians (i.e. whatever protestations they make, they are not really intent on honouring the Lord, thus they do not share common ground with us). Note that this move can work both ways in binary opposition: "A Liberal Christian is not a real Christian" say conservatives, "since basically they are heretics"; "Conservative Christians are just bigots (which effectively means, 'not genuinely Christian')" say liberals.
Thirdly, we all belong to the Lord: 'whether we live or die, we are the Lord's' (14:8). Our common ground is that we belong to the same family of God. Consequentially Paul goes on to ask, 'Why do you pass judgment on your brother or sister?' Again, see in the above paragraph, number (2): the simplest way to avoid the complexity of handling difference in a Pauline manner is to deny that the other is a member of the same family!
Is that the end of the matter, we are different but the same, so just get on with life? Not quite. As time permits I will come back to Romans 14 and 15.