Words - the snide ones

I have noticed that when engaged in a light hearted, spirited, or even heated discussion regarding opposing perspectives, civility doesn't seem to be a part of the equation. I think I can safely say that it likely is never a part of the equation. Unfortunate as that may be I do feel it is accurate to say.
I think the main problem is often the wrong emotions come into play and those emotions make people say snide remarks. These sly insinuations often are tremendously disrespectful, offensive, inaccurate, and down right painful. Throwing snide words at someone, is with the intention of making oneself feel less vulnerable and more in control. Fear, jealousy, anger, lack of compassion, inability to be empathetic and many more of those negative emotions are largely at fault for the poor choice of words used in many so called debates.
I do think personality is another contributing element to one making snide remarks. Ones insecurity, lack of self worth, poor attitude, character flaws, and many others add fuel to the fire.
I guess what I don't understand is why can't people see, know, understand, respect and accept the fact that we all have our own perspectives, perceptions and personalities?
Those are the things that make us individual and unique from one another. My perspective is only mine and cannot be owned by anyone else. My perception is what I take away from my observations regardless of the intent of the those I observe. My personality is what my DNA, my nurture and my experiences in life have given me. How is it that ones opinion of something is better or worse than another's opinion?
It is really simple don't you think, when you really think, hard and serious? Come on...give me any good reason why can't we have a disagreeable discussion without snide remarks?