There seems to be two kinds of socialists in the libertarian movement:
I disagree with the premise that "many active so-called libertarians are socialists in libertarian clothing."
Naive socialists - people so wrapped up in socialist culture that they have a difficult time thinking outside the
socialist bubble. They drag along a great deal of socialist baggage during discussions of what they think are
libertarian discussions. This is the larger group of the two. As soon as the going gets tough in discussions
they revert to socialist thinking. Some can be reasoned with to some degree but many cannot recognize
the danger of their constant reversions. [On the other hand I am often accused of being the opposite and not
holding basic libertarian ideals either].
The second group is the one of real concern. Socialist activists acting as libertarians. The percentage varies
from one discussion group to another, one group of writers to another, and among libertarian groups. They
are hired or self planted internal saboteurs. Anti-war protest/anti-nuclear/environmental groups are full of foreign
hired and socialist group hired and paid for influence peddlers - those tenticles branch into libertarian groups
when libertarians work with socialist groups in common cause. Not a pretty thing and libertarians seems to have
a naive streak about the issue. Put it this way - when I was in the Air Force we got security briefings about
foreign spies. Those briefings only concerned conventional full time spies working directly for foreign governments
directly seeking military secrets. Basically every city with any military base or military contractors had foreign spies.
The more interesting and larger numbers are when you talk about economic spies [estimated at 3,500 full time from
China alone], plants in the media in the hundreds, plants in politics - at least dozens at any given time, and so forth.
Unelected government bureaucrats - likely huge numbers. Only estimates but you can be sure that there
are many pretend libertarians in the mix.