I assume because life is connected to these outlooks & the future of earth or countries would depend on it. There would be always two kind of people, Liberal or conservative. Some times it's crucial that how many % of people in a community take one of these sides. For instance, a country like India, only few big cities progressed & accepted technology & being connected to outside world & new things, but most of the country is going by tradition for example in so many villages when they get poisons by snakes which is common, they don't accept medicals & medicines, they do attempt for healing on their own with their tradition ways.
So the discussion & kind of battle of liberal & conservative in bigger views will exist cause any changes would decide the future lifestyle in so many aspects for both sides. That might be the reason people get into it a lot.