Libertarians maintain that one of the most fundamental freedoms a human being can have is the right to be left alone. On an elementary level, this means a person should be free from others who wish to bother them, but what it really means can be shown with an example. Your country decides it has to go to war with Lower Slobia. If you thought that was a grand idea, you could volunteer to be a soldier. Otherwise, you could say, “I am not interested in your war, so leave me alone.”
If you wanted to use a drug, then that is your choice. As long as you did not impose your will on anyone else, you are free to do as you wish. In a sense, it follows the Christian Golden Rule with a slight twist: Do nothing to me you would not like done to yourself.
Although there are problems with this point of view, libertarians understand it because they have actually thought about it.
Conservatives have a tendency to see society as a collection of people with shared goals and values.
A government is something a society creates. Things like gambling and drug use should be controlled because it is the proper function of a society to maintain certain standards that benefit the whole. Abortion is a very bad idea because it allows the killing of human life, justified only by the whim of another.
Liberals, especially the far left, think of society almost exclusively as government. Their argument would be: If you are free to do as you wish, you are actually asking to be free to harm others. What appears free in your choice may create societal costs. Those costs justify society (read government) in restricting your freedom.
Remember Obama’s now famous remark about businesses “not earning” what they had. Your freedom is not free, therefore society has a right to restrict your freedom. Lower Slobia may conquer us, and that would be bad for our society as a whole, so it is well within the rights of society to force you to serve as a soldier.
While there is some merit to this argument, it is basically a tautology. It could be argued that anything a member of society does influences society, therefore society has the right to proscribe everything a person does.
This is complicated by another feature of liberal ideology. The far left won’t leave you alone because they can’t. Modern liberalism is Messianic. They are dedicated and centered on creating an earthly paradise. The goal itself is so important that the ends justify the means, or as Stalin supposedly didn’t say, some eggs must be broken to make an omelet. Opposition to this goal is also seen in Messianic terms. It must be evil, and as such cannot be tolerated. Society must, therefore, control, restrict, and ban certain behaviors, even certain terms and words, which may indicate people may not be thinking properly, which in itself may become a crime against society.