I've never heard that Fox has explained their slogan.
Perhaps they think they're "fair & balanced" in the context of being the opposition to leftish news sources?
What they seem to be best at is re writing history. Reagan got caught in the Iran-Contra weapons sales and to hear Fox tell it he never did anything wrong. Probably because of the massive tax cuts he gave the richest people in the country......even though he borrowed the money from foreign banks to do it. Take a look:
Historical figures from the bureau of the debt:
....................................Total U S Debt.......................................
09/30/2009 $11,909,829,003,511.75(80% Of All Debt Across 232 Years Borrowed By Reagan And Bushes)
09/30/2008 $10,024,724,896,912.49(Times Square Debt Clock Modified To Accommodate Tens of Trillions)
09/30/2007 $9,007,653,372,262.48
09/30/2006 $8,506,973,899,215.23
09/30/2005 $7,932,709,661,723.50
09/30/2004 $7,379,052,696,330.32
09/30/2003 $6,783,231,062,743.62(Second Bush Tax Cuts Enacted Using Reconciliation)
09/30/2002 $6,228,235,965,597.16
09/30/2001 $5,807,463,412,200.06(First Bush Tax Cuts Enacted Using Reconciliation)
09/30/2000 $5,674,178,209,886.86(Administration And Congress Arguing About How To Use Surplus)
09/30/1999 $5,656,270,901,615.43(First Surplus Generated...On Track To Pay Off Debt By 2012)
09/30/1998 $5,526,193,008,897.62
09/30/1997 $5,413,146,011,397.34
09/30/1996 $5,224,810,939,135.73
09/29/1995 $4,973,982,900,709.39
09/30/1994 $4,692,749,910,013.32
09/30/1993 $4,411,488,883,139.38 ( Debt Quadrupled By Reagan/Bush41)
09/30/1992 $4,064,620,655,521.66
09/30/1991 $3,665,303,351,697.03
09/28/1990 $3,233,313,451,777.25
09/29/1989 $2,857,430,960,187.32
09/30/1988 $2,602,337,712,041.16
09/30/1987 $2,350,276,890,953.00
09/30/1986 $2,125,302,616,658.42
09/30/1985 $1,823,103,000,000.00
09/30/1984 $1,572,266,000,000.00
09/30/1983 $1,377,210,000,000.00
09/30/1982 $1,142,034,000,000.00(Total Debt Passes $1 Trillion.....Reagan Slashed Tax Rates To Pre Depression Levels)
09/30/1981 $997,855,000,000.00