Metal Fact #1: Everyone is fucking huge in Brazil and Japan. EVERYONE. Bands that barely ever enter the United States will do whopping South American tours.
Metal Fact #2: No one is huge in Russia*. That's still where all the scariest fans come from though.
Actually, metal is just wierd like that. The most charming thing about it, I think, is the global appeal it seems to have. Metalheads are fucking everywhere.
Also, from what I've read Martins reasons for leaving were more complicated than that. There was friction developing between the members of the band, and, relevantly, I remember reading in an interview shortly after that the refusal of the rest of Skyclad to travel to South America for a tour because they were worried about their safety there prompted a massive row which crystallised his desire to quit. By all accounts, Martin has an absolutely corrosive personality. He certainly does have a talent for breaking up really great bands. He's becoming a full-time writer now, they had an interview with him in Terrorizer.
*Except Gorky Park, and they SO don't count.