The word "national socialist" is a proper noun, and all proper nouns start with capital letters. 
I guess it's a good thing you're not a grammar national socialist though considering you just used a comma splice.
Actually the funny thing is most internet grammar national socialists do not actually know much about grammar. You can trip them up on semicolons, comma splices, using the word
however incorrectly, incorrectly using who/whom, ending sentences with prepositions (eg what are you talking
about), etc.
http://en.wikipedia.org/wiki/Comma_spliceMy view is that anybody who calls themselves a grammar national socialist and does not have a copy of the
Little, Brown Handbook within immediate reach is a wannabe grammar national socialist.