Granted, there are some people that drink the koolaide of whatever political philosophy that is their favorite and tend to be very zealous and unthinking in their debates -- down along the level of spouting bumper sticker slogans in a rally. I believe if you engage those people one-on-one and start stripping away the hype to find out what they really mean by this or that term and whether they have really thought through their political philosophy and its implications, you are likely to find one of three things:
(1) A nice person (nice, but misguided judging by your own system of truth) who really believes what they say and truly has compassion for people around them and has truly thought beyond the bumper sticker slogan to how their philosophy plays out in a daily life and actually lives by that philosophy;
(2) Or a person that has thought through all that but takes logical leaps and broad assumptions for truth, a moving target during debate or calm discussion, because they do not want to have their beliefs challenged, and any amount of argument you may have with them will devolve into ad-hominem attacks and raised blood pressures for you. They will not budge on their opinion, don't enjoy discussing it, and see debate merely as a war of attrition where they hope to wear you down. For them, it is no longer about truth but rather it is an attack on their character or person, their very psyche (and they have some deep-seated pain or animosity that drives them to cling to this system);
(3) Or normal human being like yourself that has just not been taught to think more broadly and consider all possible opinions before picking one that seems to correspond best with the system of truth or religious beliefs that he/she has chosen. You may even find that the person does not fully understand the ramifications of their chosen system of truth or belief.
Often, young people fall in this category because they are impressionable and do not know enough about life to sift out what is just ordinary dirt and what is gold. They usually end up following the opinions of their parents if they have a reasonably good relationship with their parents, or they follow their peer group, or they seek out an older, seemingly wiser or cooler person out in the world that they emulate. That is, they lean on the external opinion until they day that they start thinking for themselves and realizing that they have as much to contribute to the search for truth (so long as they are grounded in a good system). Unfortunately, some people don't grow out of that stage. They continue to stay in the same rut of thinking, good or bad, that they chose in their youth, and take it verbatim without challenge or question or without demand that it correspond to some external system of truth (such as the Bible).
Everybody comes from a different place in life based on their upbringing or experiences. Sometimes it is helpful to know where they are coming from, perhaps what logical or moral baggage that they bring with them into a discussion, maybe recognize when they are just applying labels and not really thinking through. But it is always good to remember in a debate, that the person in front of you is still a creation of God and loved by God just as much as God loves you. And it is always good to remember that you may have more experience and a better system of belief, but that doesn't mean that you are yourself the source of truth. You are merely relaying as best you can understand in this sin-cracked lens of a mind what God speaks to you through the Bible or personal interaction in prayer or even the thoughts, letters, or sermons of others which seem to resound with His voice. But always, as Paul said in 1 Corinthians 13, "we see through a glass dimly."