Humbled - We all cherry pick scriptures : ) It's impossible to use the Bible as a Guide without doing this.
Many claim that Gentiles are / were under the "Noahide" Laws 7 Laws apparently given to Noah, when he left the Ark. It is said that All Humans are under these Eternal 7 Laws.
I personally feel that all Humans should Folllow The Proper Mosaic Law. The confusion comes from statements such as "For the whole law is fulfilled in one word: “You shall love your neighbor as yourself.” (Gal 5:14 )
Some take this to mean, that the Law of Christ is Simply Love of our fellow man, and following Principles of Love.
Gal 5:14 is not a new "christian" mentality though, the Law of God has always been summed up this way.
It is possible that the Writer of Gal 5:14 was referencing The Talmud..
The Talmud in tractate Shabbos 31a relates the following well-known story of Hillel: "On another occasion it happened that a certain heathen came before Shammai and said to him, "Make me a proselyte, on the condition that you teach me the whole Torah while I stand on one foot." Thereupon he chased him away with the builder's cubit that was in his hand.When he came before Hillel, (he also asked Hillel to teach him the entire Torah while standing on one foot) Hillel replied, "What is hateful to you, do not do to your neighbor: that is the whole Torah while the rest is commentary; go and learn it."
The point is that God's law is always summed up by fewer but Greater Laws. The most important of these laws being Love.
So in regards to the Laws placed upon Gentiles at Acts 15:20.. Abstaining from blood,Imorality and food sacrificed to idols, are important requirements, but they are not the only requirements.. (Murder?)
Acts 15:21 gives an important clue.. " For from ancient generations Moses has had in every city those who proclaim him, for he is read every Sabbath in the synagogues.” This can imply that the prohibitions of blood, food sacrificed to idols and fornication were summaries of smaller laws, in addition to the Well Established teachings of Moses (Torah) , which were so fundamental, they were read in The Synagogue weekly.