That's fine if you want to believe that, but when I read Romans 14:5-6 I think that includes the Sabbath. I believe Romans 13:9-10 puts it best, LOVE IS THE FULFILLMENT OF THE LAW!!
Yes; Jesus Christs, is "LOVE THE FULFILMENT OF THE LAW" ---not your or my or anyone's 'love'.The Law of Love is the one Law no one can ever,fulfil. We just dont have, the capability or capacity of that "love" that "is the Fulfilment of the Law. Only God who Himself "is Love", has the capability and capacity of that "love" that "is the Fulfilment of the Law.
Now Romans 14/15 least of all deals with that Love; it deals with mans LACK of that Love. Nor does Romans 14/15 deal with any issue concerning the Sabbath.
Let us restrict ourselves to what Romans 14/15 actually is about, and that is men's SPITE, that will not tolerate another person may also mean well or do well.Good is reserved for the good.
No; everyone in Romans 14/15 reckoned God's Kingdom was "food and drink" that makes him look better than his neighbour. Life is a feast prepared to my recipe or its not for the Lord.
"Food and drink" - that is, a superiority-complex of exclusivity and distinction - is what Romans 14/15 is all about; You're not good enough to the Lord's judgment; I am.
Romans 14 is not about the Sabbath. Forget with how much or how little or no love anyone may fulfil the Law. It is even further off the topic of Romans 14/15.