How's being bigoted relate to this? Most people oppose killing innocent people. What is and isn't a "person" is partially a subjective judgement; people who oppose abortion might believe that e.g. a one-month-old foetus constitutes a "person", while people who support abortion might disagree. People have a right to believe that killing one-month-old foetuses is wrong just like vegans have a right to believe that killing animals for food is wrong; there's no objective answer to moral questions.