When people say there are too many abortions in society, do they have a figure in mind of what's acceptable? 100% abortions would be unacceptable, obviously, as would a number that kept the birthrate too low for a sustainable population. But what then? Would any abortion that was done as a means of birth control be one too many? Would any abortion be too many?
The problem of course is that we can easily find examples of where we can validate a sense of outrage. That we could easily do better by eradication of such waste. Perhaps it's easy to give examples of teenagers who got pregnant instead of staying abstinent and then using abortion to shirk their responsibility.
Another example is taxation. It's easy to feel outraged over government waste, that one's tax level is always going to be too high because there's always government spending on useless things. I remember a few years ago a news report complaining about a painting that the New South Wales government spent a 6-figure sum to purchase which was white paint on white canvas. Not purchasing that would have saved each New South Wales taxpayer around five cents!
The kind of argument is somewhat deceptive, as it provides a small point of agreement with the implication being the implicit support of total eradication. It's easy to gesture to a reduction, but to what extent does it entail? For those who wish to see an end to abortion, getting pro-choice people to agree to wanting to reduce abortions is really an implicit mandate for condemning the practice. Likewise libertarians will see any and all taxation as stealing, using waste as the mandate for a reduction from what there is now.
Sometimes it is important to argue for reduction, and reduction can be a good thing. Perhaps it's important to reduce spending in a time when the budget won't allow for it, but then it's too high in regard to an external constraint. The Iraq War might have cost the American taxpayer hundreds of billions at a time when there's a high deficit, but is the outrage in that case really about the money or the act of war? For those opposing the war, they would do well to steer away from the costs because their outrage is not with the fiscal cost but with war itself.
But reduction for reduction's sake is a weasel argument, a means to gather support for a position that people would otherwise find unfavourable, through finding smaller favourable elements that both sides can agree on. If I agree that funding the high arts is a waste of taxpayer money (I don't, for the record) it doesn't mean that I think taxes could or should go lower. Likewise if I agree that using abortion as a method of birth control is something bad (I don't, for the record) it doesn't mean that I wish to see the end of abortion.