That's an interesting twist. I had not ever seen it that way.
The problem with it, however, is that the two parallels you have drawn are not at all comparable between the two.
The quote about baptism includes the conjunctive requirement for baptism, therefore not at all leaving it open to preference. This is why I also study doctrines from a systematic vantagepoint:
Acts 2:38 Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.
Nobody could possibly and up saved if their sins were not remitted, washed away, or whatever relevant word one may choose that aligns with the original meaning.
That conjunctive "and" in there doesn't allow for preferentially choosing as to if one wants to adhere to the following element.
Moving your example more closely to reality, if I'm directed to make a cake with flour and sugar, and subjectively choose to leave out the sugar, it's no longer cake, but rather a more bland tasting bread thingy, and therefore not anywhere nearly as palatable to the taste as bring something that would serve as a desert.
Where did you hear that the text item joined with the conjunctive can be left to preferential choice in the biblical texts? Was it some pastor you follow who stated that to you? Is that what she teaches?
Paul, THE apostle to the Gentiles, said this:
1 Corinthians 15:1-4
1 Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand;
2 By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain.
3 For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures;
4 And that he was buried, and that he rose again the third day according to the scriptures:
There is not one mention for the requirement of water baptism here nor anywhere else in Paul's epistles, and yet there are those out there who have been taught to believe that Paul taught the same Gospel as did the eleven to Israel, which is not at all true. Intellectual honesty demands that they read the texts for what they say AND for what they DON'T say, and to refrain from injecting into the text any measure of subjective assumptions.
Additionally, there are those who would say that the absence of mention for water baptism was left to the reader's understanding that it was still there, although invisible by way of the knowledge of the reader, and therefore didn't need to be restated.
Satan very much loves that kind of reasoning. It lays down at the feet of Paul in eternity his having led many billions of Gentiles astray. After all, if water baptism had still been a required element for salvation as a show of faith, as a work for justification, then Paul would indeed be guilty under the sin of omission. Just think about the impact in leaving out just one element for salvation. Do you see the problem in that claim?
So, yes, Israel was required to engage water baptism as a show of their faith since water itself cannot remit sins. It is the WORK, the ACT, that was required of them, but not us today. Why?
Simply stated: Grace. The very definition of grace being UNMERRITED FAVOR, that should suffice in understanding the omission of the requirement to be water baptized. Attempts at coupling ANY work to grace, and one nullifies the grace. Paul made that abundantly clear:
Romans 11:6 And if by grace, then is it no more of works: otherwise grace is no more grace. But if it be of works, then is it no more grace: otherwise work is no more work.
Do you see the problem with your assumptions?
I hope you would not mind my saying that I would never set foot on a bridge an engineer told you to build from the parts he gives to you, and to be sure you use the special steel bolts provided, and you subjectively decide to put rubber bands through the bolt holes in the place of the special steel bolts. I would rather do the back-stroke across the river than to set foot onto something that will not hold up.
Good luck with that, because you're going to need it.
MM