My impression is the following: philosophy majors (or philosophy graduates) have always seemed to give the best discussions. They're better equipped and trained to provide thorough arguments and refutations. When arguing with a 'philosopher' the argument is often a step by step process, where you can point out the reasoning behind a point, which the other person has then to refute. In my experience, a good philosopher is more likely to get you (or another philosopher, since laymen work differently) stumped and convinced of the opposition's point for a while until you manage to find the flaw in the argument.
In the other hand, people that just aren't good at argument (like most people here) usually are predisposed towards a side and convince themselves that whatever point they make is true even if in poor exposition or faulty reasoning. Like what I've observed from you, they try to make a snappy one-liner and pretend that that is substantial argumentation as if you made yourself think you're good at debating by watching HBO or something.
They remind me of these kids that were arguing with a creationist on campus. I'm an atheist, and these kids were trying to make the usual "atheist points", and the creationist there was just thoroughly picking them off one by one. Yet they were acting like they made such an ironclad point that the creationist was stupid for not taking it seriously and acted like the creationist somehow just didn't understand them. Then instead of refuting the creationists rebuttal, they just repeated themselves or brought up something irrelevant. When I tried making a premise by premise argument with the creationist, some doofus yelling truisms would interrupt me.
If you think you're seeing something that I'm not seeing, I beg of you to educate me.