There are some conservative Christians who speak with great moral assurance when it's obvious that they haven't thought deeply about ethics. Of course, that's hardly confined to conservative Christians. The same phenomenon recurs regarding "progressive" Christians and secular humanists.
I'm thinking in particular of Christians who rely on a handful of zippy labels and catch phases to evaluate a position, viz. That's situation ethics! That's consequentialism! The end doesn't justify the means! Of two evils, choose neither!
There are Christians who think ethics is easy. They imagine they can wing it with a few slogans. But ethics is very demanding. It requires careful distinctions. Patient analysis.
One common failing is people who don't stop to consider any counterexamples before they make blanket claims. But a thoughtful person, especially a Christian, should cultivate the habit of considering exceptions or counterexamples before presuming to generalize.
For instance, suppose you're diagnosed with terminal cancer. What should you do? Well, that depends. Since treatment is futile, it might seem pointless to undergo treatment. But it isn't always that simple.
Suppose you're 2 years shy of retirement. Treatment will prolong your life. If you can make it to retirement age, your wife will have your pension to live on. But if you die before then, she will be in dire financial straits.
So even though you're doomed, it makes sense in that situation to undergo treatment. Conversely, if you're a widower with no dependents, then it might be more sensible to forego treatment.
Or to vary the illustration, suppose you're the father of two adolescent kids. Now is a very bad time for you to die. Bad for them. It makes sense to undergo treatment to buy yourself some extra time with your kids.
Let's consider a more controversial scenario. Suppose you see a house on fire, and a young boy in the second floor window. Should you rush in to save him if you can? Normally, you have a duty to intervene in that situation.
But suppose you have second sight. You realize that if you save him, his son will become a security guard, on the night shift, at a petroleum refinery. He's supposed to do the rounds every night to make sure no systems are going critical. If they are, he must sound an alarm to evacuate the company town next door.
But he's derelict. As a result, the refinery explodes, incinerating the town, killing a 1000 residents. If your intervention has that delayed effect, should you save the boy? We could debate that–which is the point.
Although some moral issues are clear-cut, there are other moral issues where you can't take intellectual shortcuts. You can't be morally serious and morally superficial at the same time.