Sure, an argument can include terms such as "wrong." But that isn't doing much to determine what is wrong. Morals are a zone where emotion is very much involved. We argue/persuade because of such emotion.

I think he's saying that "right" and "wrong" are broad terms that need to be associated with something in order to have meaning. Generally, if something is harmful to another it is considered "wrong", and if it promotes happiness it is considered "right". These are just semantics, we all know what someone means when they say right or wrong. I believe the confusion comes from this idea that there is some absolute truth where behavior is inherently correct or incorrect regardless of the circumstances. If you believe this, as many people do, it is indeed difficult to define right or wrong. We define right and wrong by the consequences of our actions, but if there is a right and wrong regardless of consequence, we have no means of explaining why.

I just explained, if you believe that something is "wrong" just because it is "wrong", then you are not using logic. If someone believes that there is an absolute right or wrong, such as whether you should lie, then consequences are irrelevant. Therefore, they are just following rules without any logical reasoning behind them.

EDIT: I'm not trying to say that this is how I believe, merely that this viewpoint towards morality offers serious logical flaws.

I still think he is creating a logical fallacy. Just because something is wrong in one circumstances it does not make it wrong in a completely unrelated circumstance. It's similar to the fallacy of not agreeing with an opinion simply because of who you heard it from. If you do not like Peter Singer because he allegedly eats meat and therefore you decide you shouldn't be a vegetarian, you are coming up with a conclusion that does not follow the premise.

What Kant argued was that if everyone (say) lied when he thought the consequences of lying on that occasion were good, then he would be saying that everyone should lie when they thought the consequences were appropriate. Why, after all, Kant asked, would it be all right for you to lie when you thought it would be a good thing, and not for others? But, then, suppose that everyone could decide on their own, on any occasion, whether to lie or not? What would be the consequences of that? No one would be able to trust anyone to be truthful, because how could anyone know that the speaker had not decided that on this occasion, it would be all right for him to lie. The institution of people trusting others would simply break down. What would this mean for society?

So, you see: 1. Kant did not argue that something is wrong because it is wrong. and, 2. He did certainly take consequences into account.

Of course, you may disagree with Kant about this. But would you disagree with him because he was not logical, or just because you thought he was wrong? There is a difference?

I disagree with him because he was not logical, and here's why...
This discussion is not about what someone thinks is right or wrong, it is about whether or not a lie can ever be right in any situation. Let's do an example. Mary decides to lie to John by telling him that her baby is his in order to collect child support. She has justified this in someway to herself, and in her opinion it is the right thing to do. But in reality, it is hurting John financially and emotionally. This lie is clearly not providing a beneficial moral outcome. But let's say Mary decides to lie to John by telling him there is no baby because he is a baby-killing lunatic who would snap its neck if he was aware of its existence. She has also justified this to herself, but this time the outcome does have a beneficial moral consequence. In both cases she has perceived a right and wrong, but in only one is she correct. Whether or not people will abuse the justification of lying is irrelevent, because it does not change the fact that a lie is or is not harmful. Kant is using a slippery slope arguement to try and justify his position.
Kant is basically saying that lying is always wrong because someone may use the fact that it is sometimes right to justify it when it is wrong. This is hypocritical and paradoxical, and absent of logic.