Not every person accepts the Bible as authoritative, thus they cannot be expected to comply with its demands just because you choose to. That is a simple fact and one protected by the US Constitution, it is called FREEDOM OF RELIGION. You are not allowed to force your religious views on another person. You may personally hold whatever views you want, but forcing another person to hold your views is anti-American, nor is it loving, which makes it anti-Christian. The Bible never teaches that you should FORCE its teachings on another, you may present them, show by your own life that you live them and hopefully your life is righteous enough that another wishes to follow your lead, but you are not to force them on the other person. Those who attempt to force their understanding on others are called in the Bible Pharisees. Are you a Parisee?
You're changing the subject from "Is it morally wrong?" to "Can the government force you to agree?"
Those are not the same question.
A Christian arguing that abortion is the intentional taking of innocent human life is making a moral claim, not establishing a state church.
Freedom of religion means the government cannot compel worship or prohibit it; it does not mean moral arguments are disqualified from public discussion.
By that logic, a Christian could not oppose theft, murder, perjury, or exploitation if his reasons came from Scripture.
The real issue is whether the unborn are human beings and whether intentionally killing innocent human beings is morally permissible.
Simply saying, "Not everyone accepts the Bible," does not answer either question.
People disagree about every moral standard, yet laws still exist because societies make judgments about right and wrong.
The Pharisee comparison also misses the target.
The Pharisees were condemned for hypocrisy, elevating their traditions above God's word, and burdening others while refusing to obey themselves (Matthew 23).
Merely appealing to Scripture as an authority does not make someone a Pharisee.
In fact, if two Christians are debating what Scripture teaches, then both sides have already accepted Scripture as the authority under discussion.
The question becomes: what does the text say?
If the text presents the unborn as children in the womb, known by God, formed by God, and never excluded from the command against shedding innocent blood, then the argument must be answered from the text itself, not by appealing to constitutional rights or religious pluralism.
The world-system being echoed here is relativism: shifting the debate from whether something is true or morally right to whether everyone agrees with the authority being cited. Truth is not established by majority acceptance, and Scripture never teaches that a moral claim becomes false simply because some people reject God's authority.