Why is it so hard to reason with pro-lifers?

[Gawdzilla Sama]

The issue of abortion resolves to metaphysical beliefs about being human and when that begins.   It's a set of assumptions, whichever side you are on, and so is resistant to reasoned approaches.  So emotion and propaganda tend to be the tools of choice for both sides.  And given that, for the pro-life individual, the stakes are life and death, it's not surprising that it gets highly emotional and irrational.  It resolves to a political question of who can enforce their beliefs on whom.  That's bound to get heated, as any other political issue does.

I agree with your post, though to be fair, only the Pro Lifers are trying to enforce beliefs  -- on pregnant women. 

Pro Choice just want the women to have a choice -- they don't go around trying to force abortions on people.

I don't think Angrboda was implying that both sides were trying to force their beliefs on people.