Rightwing: Why Considered Worse Than Leftwing?

As this Blog has previously shown - of all the the significant European dictators, Franco alone was a rightist. (Portugal's Salazar - arguably.)
The BNP and EDL and what remains of the National Front are all parties of the left with a nasty agenda - and so we class them as being of the right. - Odd, innit?
I am reminded of the communist commissars who fought against Gorbachev's reforms in the USSR - astonishingly our leftist media regularly referred to them as - yes, you guessed - 'rightwingers'.