I regret nothing (caution: rant ahead)

Personally, I agree with what was said on the plaque. That was a pretty low thing for you to do. Try not be such an asshole next time. You sound judge-mental. I know many Christians that are in no way homophobic. I'm siding with the pastor on this one. What was written on the plaque is in no way an extreme view. Their should be no reason why you had to act the way you did.

 

I think it's fine for people to honour those that were aborted, as long as they don't demonize the mothers or try to prevent them from having abortions when they aren't capable of raising the child.

I think being respectful of this kind of thing is the best avenue. You might not change many minds by tactfully expressing your point of view, but being rude about it will just make you out to be the bad guy.

 

The problem here is that if you strongly disagree with an opinion, you have an obligation to yourself to do what is necessary to delegitimize that point of view. If you allow a point of view to be viewed as respectable, you do nothing to undermine it. In fact, you give it legitimacy, simply by the fact that you allow people to think that respectable people can hold it.

How far you are willing to go is directly correlated with how strongly you feel about a particular issue.

To give an example, I feel very strongly that teaching a child that being gay is bad or wrong is completely unethical. My goal is to stop this practice, and to make it completely unacceptable in our culture and for there to be social consequences for those who engage in it. I may encounter someone who I like on a personal level. Who, by all other measurements, is a decent person. However, for whatever reason, perhaps for religious reasons, believes that being gay is a sin. Therefore, they are committed to teaching this to others, particularly children. If I want to stop this practice, it is essential that I get society to view it as completely unacceptable. I fail at this if I allow it to be seen as a respectable position to hold, because that allows it to maintain its legitimacy.

So, how do I combat this problem? I put aside my personal feelings for this person, and I ignore any redeemable qualities that they may possess. It is usually impossible to convince someone to change their point of view. However, you can make an example of them, and you can intimidate or humiliate people into stepping down. So, I ask this person if they would tell their child, if he or she were gay, that being gay was a sin. If they say yes, I would press them on this point, asking whether or not they would continue to tell their child that being gay was a sin if they knew their child was suicidal as a result. If they say yes, I would continue to press them, and I would paint them to be a horrible monster.

Now, the truth of the matter is they may be a wonderful parent in all other ways, and the likelihood of them having a gay child is extremely small. However, none of this is the point. My goal is to convince the people who are listening or watching that this person is evil, that they would sacrifice their child on the alter of their religion. This shifts the entire debate away from whether or not being gay is a sin--a simple matter of opinion, based around whether or not you agree with a particular religious doctrine--to a moral and social argument that we need to have on how we treat gay children. This is much more favorable terrain for me, and it puts my opponent on the defensive. They have to justify their actions, and I am going to try and make them prove that they aren't a monster. My goal is to delegitimize their position in the eyes of others, and as a result create social situations in which parents can no longer freely act in this way without social--if not legal--repercussions.

How far you're willing to go is directly correlated with how strongly you feel about a particular issue. If you don't feel very strongly, you may show mild disapproval, as happened in the OP's situation. If you feel very strongly, you may opt for direct confrontation. If you feel very weakly, you may simply do nothing, or 'agree to disagree'. However, a culture only changes to favor your position once the old position is no longer acceptable in the eyes of the majority. To achieve this, you must delegitimize it. It is a mistake to believe that people change their opinions based on well reasoned arguments (not that we shouldn't formulate them anyway, of course) or through good will discussions. In fact, the more evidence and the better reasoned your argument, the more convinced your opponents become that they are correct. Most people only change their opinion when their social group changes their opinion.

If you want me to back up my claim, this article discusses the research into the matter.