This bumper sticker is true. However, I think that many people misunderstand the truth of it. Most of the time, when people say "when you choose the lesser of two evils you still choose evil", they use it as justification for not choosing at all. Making no choice is wise when you are choosing between sinful things. For example, if you are trying to find a movie to watch and all the choices are bad, not choosing one would be the best choice. If all the choices are dishonoring to God, it would be better to watch nothing. If you are trying to watch what you eat and the only food you are being offered is junk food, eating no food would be the best choice but at some point, you have to eat something or you will die of starvation. So decisions that don't carry a lot of weight can apply this logic, but the more weighty decisions might require us to choose something that is less than the best. In fact, some times, not choosing could be an even greater evil than the evils you have to choose between.
Let's look at a few examples where choosing the lesser would be better...
First example: Suppose a man with murderous intentions has one of your loved ones held hostage. Somehow, the murderer to be contacts you and gives you a choice. You have to decide between your loved one being murdered or maimed. Both choices would be evil. However, a mutilation is much better than a murder. The lesser of two evils is the right choice to make because it spares the life of your loved one. Making no choice doesn't choose one of the two evils presented, but it could be the greatest evil in the situation. Not choosing means you are leaving the fate of your loved one up to someone with murderous intentions when it was within your power to save their life. Wouldn't choosing the lesser of the two evils be the right choice over choosing nothing at all?
Second Example: Let's suppose you are given the option between losing a finger, losing a hand or letting someone else choose for you. I wouldn't want to lose either, but that isn't an option. All three choices would be bad for you, but you can do a lot more with 9 fingers than you can with 1 hand. All the choices are evils because they cause you bodily harm, but losing a finger is the lesser of the evils. Plus, the evil of losing a finger is better than the evil of losing a hand. Letting someone else choose for you might result in you losing your hand. Why would you let someone else have the power to cause you a greater harm when you could have chosen a lesser harm? Only a fool would make the choice to choose nothing in this scenario. The choice isn't good, but it is better without being the best.
Third Example: What about the future? Imagine you were saving for retirement and had accumulated $500,000. What if you were told that you would lose half of your savings or all of your savings? In this situation, that choice is completely up to you. Its going to be bad either way. We could say both choices would be evils. However, losing half of your life savings is a lesser evil than losing all of your life savings. Wouldn't you rather have $250,000 than $0? Of course you would. Anyone would. Keeping it all would be the preference. That would be good. Sadly, good isn't a possibility. That possibility doesn't exist in this scenario.
In these three examples, when presented with only bad options, its wise to choose the one that causes you and others the least amount of harm. I think it is pretty clear, picking the lesser of two evils can be the right choice. It is also important to remember that when we do that, we are still choosing an evil. A lesser evil might be better than a greater evil but that doesn't make it good. Sometimes though, good isn't an option. It's at those times that we must choose the lesser evil. We should certainly pray and seek God before making such a choice. Consulting godly council would be wise. If it becomes clear we must choose the lesser evil, what should we say about it? Certainly we refrain from calling the lesser evil "good". It might not be as bad but it is still bad. It might not be the most evil, but it is still evil. So we need to make sure we understand that and others understand it too. Sometimes we will be forced to choose between two evils. When we are, we must do so in such a was as to ensure that things aren't as bad as they could be. In doing that, we must never call the bad, good or the good, bad. Only God is good. Evil, even when lesser, will never be good.