I think most normal people do. Well-adjusted people grow out of it.
I myself played with liberalism in my 20s and most conservatives I know today did the same.
I belonged to a group called Arms Race Concern when I was in my late teens/early 20s.
So the above is why most NORMAL people do?
Dabbling in liberalism in your twenties has nothing to with being normal or abnormal. It probably has more to do with maturity/immaturity.
BTW, I never fell for liberalism. Neither did most of the conservatives I know. And I'm proud of it.