That oversimplifies things a great deal.

First, most people don't have a single yes/no answer to point 1, and for better or worse they probably don't view "human being" as a binary state. Some of them believe that a fetus gradually becomes a human at some nebulous point in time, some believe that it's a "potential person", some believe that it's a person with caveats. Secondly, a decent chunk of them also believe that non-humans should have some moral right, and that there might be situations where the state has a compelling interest in preventing certain outcomes even where there is no clear individual harm (for example, a nontrivial number of people are uncomfortable with constructing high-level systems to allow abortions on the basis of neurodivergence, even if they believe that each individual abortion decision on its own is justified).

But lets say someone answers #1 with, "yes, and they should have full human rights". Then we go to point #2, and the short answer is that people who believe that it's literally never moral to intentionally kill someone are exceedingly rare (I've gotten to know maybe one person total in my entire life who I considered to be genuinely a strict deontologist). Utilitarianism is also not a binary conclusion for most people, most people believe that individual rights are worth protecting in at least some cases where they could intentionally be used to cause harm, but in other cases should be blocked because of the outcome -- and they often differ on where they draw those lines and what rights they think are most important to protect. The vast majority of people in the world tend to be somewhat utilitarian in some situations, and somewhat deontological in other situations.

So now there's question #3 which you hint at but don't actually raise -- are abortions intentional deaths or are they closer to the scenario you describe with ectopic pregnancies, where the actual goal is just the removal of the unborn and protection of the mother and as a side effect the unborn dies? This is somewhat closely related to the privacy/autonomy argument that gets brought up; that trying to save unborn lives is great and if you can keep an aborted child alive you're welcome to do so, but that concern has to be subservient to preserving bodily autonomy and preserving the patient's health -- in other words, I've heard people argue that abortion is primarily about stopping pregnancy, and that the death of the unborn is just an unfortunate side effect. And once again, a lot of people don't have binary opinions about that either; it's not uncommon for me to see people who draw lines at very different places and based on very different criteria even when they at first say something that sounds like a simple yes/no answer. Culpability for harm in general on many issues can be complicated to talk about sometimes.

And then we go on to question #4, which wasn't brought up at all: regardless of the morality, how prudent is it to legislate abortion? And once again, there are a diversity of opinions on this, not just in regards to abortion, but in regards to the fundamental question of when and how our government should legislate morality even in situations where someone with moral value is getting hurt. In fact, a large number of US debates that are separate from abortion also intersect with this question. Some people believe that the state needs to preserve absolute autonomy regardless of the morality, some people believe that it would be reasonable for the state to impose morality in some cases, but that it's likely to get it wrong or have so many unintended consequences that it should only rarely impose morality. This also intersects a little bit with the privacy arguments people raise: is the government qualified to make broad rules about very individual health/parenting decisions, especially regarding risky pregnancies -- and is it reasonable to ask people to "prove" to the government that their pregnancies are risky?

And then of course question #5, which is whether abolishing abortion is the most effective way to reduce abortion. See also drug legalization, where you'll occasionally run into strict drug critics who believe that recreational drug use is harmful and should be discouraged, that still want to see it legalized. Once again, most people don't have a binary answer to this question because there are a lot of restrictions and regulations a government can impose beyond just banning/allowing something, and even people who are primarily concerned about reducing abortion rates might disagree about which policies actually work to reduce abortion rates.

All of those questions, on their own, will get you different answers if you ask different people. The problem is that saying no/yes to each question isn't enough on its own to create a perfectly logical policy that everyone in the world will just agree with based on first principles. There are a lot of possible answers someone might give to both questions that boil down to either "sometimes...", or to "yes/no, but..."

And that's not to say that there aren't better or worse answers to those questions, it's just to say that a lot of people claim the reason conversations about abortion are stalled is because there's nothing else to talk about and everyone knows perfectly what they believe and there's no way to sway anyone, and in reality it's more that conversation is stalled because public opinion isn't perfectly resolved and many people just feel really uncomfortable and confused talking about it because it's very contentious and has a lot of stigma -- which ends up being kind of self-reinforcing because the more that people reflexively avoid the topic the less they tend to learn about it and the fewer opportunities they have to try and nail down their views.