Your experience is relevant, but consider how pro-choicers have members who gun down people in church, harass their opposition in every venue, and engage in frequent lying and shifting goalposts, while the other side occasionally loses patience after constant provocation. Pretending the latter is being unreasonable or must work even harder is dubious.

I think it's human to have an angry mean side, but that does not mean one has to accomodate or respect those flaws, or let it be used to control the frame. Zealots play upon a common decency to avoid direct discussion of their goals and tactics as offensive.

One can't point out an alternate political path without some idea the current path is wrong. If one takes extreme offense at all dissent, accomodation is impossible. It's like an angry drunk saying any reaction validates their fight. One should refrain from swinging and be willing to engage if they sober up, but until one doesn't have to be nice about kicking them out.

Pro-lifers can make polite conversation to pass the time and in hopes of conversions, but they're goal is still to bully people into leaving. Momentary civility helps them pretend they are merely decent people despite deliberate intimidation, invective and tacit or open support of the more violent among them.