Once an uncircumcised Gentile has been called, he can no longer obey the Law of Moses which specifically commands circumcision to be done on the 8th day (Leviticus 12:3). He is therefore exempt. However, he is not exempt from having his son circumcised as per the command. This is "the keeping of the commandments of God".
1. That is an assumption - without one example of that in NT or OT. it is at best, inference.
2. Babies are not born circumcised so the 1 Cor 7 command would not require that they be circumcised if their father was not or if they were not considered already to be Jewish by mater lineal rules.
3. The TEN Commandments were unique in that they were kept inside the ark - the rest of scripture was not. In Eph 6:2 we are told that the 5th commandment is
the "FIRST commandment with a promise" -- that can only be true of the TEN. So we know that there are examples where Paul's use of the term "Commandments of God" are first and foremost considered to be the TEN. A likely definition in 1 Cor 7 "
Circumcision is nothing, and uncircumcision is nothing,
but what matters is the keeping of the Commandments of God." Though it is more likely that this is a contrast between moral law that defines sin -- vs ceremonial law that does not.
4. Paul's statement in Galatians about Titus does not leave a lot of room for what you are suggesting. AT the very least he would need to limit that statement by "but Titus is encouraged to circumcise his children" or something of the sort. You cannot have the negative form as the only form in print - with the positive instruction you have suggested merely left to the imagination.
Gal 2
2 It was because of a revelation that I went up; and I submitted to them
the gospel which I preach among the Gentiles, but
I did so in private to those who were of reputation, for fear that I might be running, or had run, in vain. 3 But
not even Titus, who was with me, though he was a Greek, was compelled to be circumcised.
Paul points out that Titus is not compelled "though he was a Greek"
he does not say "
because he was not an infant". Paul does not indicate that the issue is whether or not someone is an infant. But rather - whether or not someone is Jew or gentile.
I am not in a position to argue against gentiles being circumcised as a good practice for health reasons. But Paul is very specific about the fact that there is an extreme practice in place uniquely among christian jews - not even found among non-christian jews - trying to get gentiles circumcised.
5. Notice that in Acts 21 Paul is falsely accused of
telling Jews not to circumcise their children. He is
not accused of telling gentiles not to circumcise their children. It is very very doubtful that his detractors imagined he was insisting that gentile children be circumcised -
but not Jewish children. I think this is
very problematic for the suggestion you are making especially given that you have not one example of what you propose in either OT or NT.
In Acts 21 when contrasting this accusation against Paul with what the Acts 15 council commanded -- James says this .
20 And when they heard it they
began glorifying God; and they said to him, “You see, brother, how many thousands there are among the Jews of those who have believed, and they are all zealous for the Law; 21 and they have been told about you,
that you are teaching all the Jews who are among the Gentiles to forsake Moses,
telling them not to circumcise their children nor to walk according to the customs. 22 What, then, is
to be done? They will certainly hear that you have come. 23 Therefore do this that we tell you. We have four men who are under a vow; 24 take them and purify yourself along with them, and pay their expenses so that they may shave their heads; and all will know that there is nothing to the things which they have been told about you, but that you yourself also walk orderly, keeping the Law. 25 But
concerning the Gentiles who have believed, we wrote, having decided that they should abstain from meat sacrificed to idols and from blood and from what is strangled and from fornication.” 26 Then Paul took the men, and the next day, purifying himself along with them, went into the temple giving notice of the completion of the days of purification, until the sacrifice was offered for each one of them.
Since James specifically mentions "not to circumcise their children" - the very subject you are addressing - he would need to also say "but concerning gentiles we did tell them also to circumcise their children" since it is certain that gentile Christians were not going to do that apart from some command.
James does not say that Paul is accused of teaching Jews to dishonor parents, or break the Sabbath, or take God's name in vain.. or to break any of the TEN Commandments. The "solution" James gives is not "show everyone that you honor your parents and that will solve the problem" or "show everyone that you keep the Bible Sabbath as given by God". He specifically points to circumcision and the ceremonial system as it pertains to Jews - as being that which Paul is accused.
What is more Paul is only accused of telling Jews outside of Israel - in the lands of the gentiles --- to ignore what the Bible says in that area.