To understand liberals, you must understand the nature of the left wing. They believe in powerful government to force the people into the mold of society they feel is best. Take some examples of when a left wing ideology blossoms into a far left ideology:
Communist Russia, Communist North Korea, Communist Cuba, Communist Venezuela, and of course, the National SOCIALIST Party of Germany.
To their extreme, the left is extremely militant, brutal, controlling. They must be, as that is the only way to bring about total equality in all walks of life, which is the goal of modern liberalism. Total equality can't be achieved without overwhelming force or threat of. It's why drill instructors yell so much.