Hahaha, never thought like that. Nice one.
However, I kinda feel the reason's not really about Roger personally, it may be:
1. Gambling. The guy didn't bet on Roger because he hadn't won GS for quite some time, then he believed Roger would won in the Olympics which had similar situation, and last perhaps on USO too. That's why he has lost so much.
2. The guy is a coach with mind "to win one needs 100+ sq" racquet, 2HBH and at least semi-western FH". And because of Roger he got too many "rebellious" students.
3. He's a nationalist and can't stand watching LiNa's unstable performance and no other good Chinese player. So he hates tennis and wanna bring down its icon.
4. Similar to no. 3, he's a badminton or ping-pong lover and hates tennis which is gaining popularity in China.
5. He owns a security company and lost the tender for both BeiJing and ShangHai Open. Now is revenge time.
PS. When I created this thread there was no thread discussing thiis topic in the first page, apparently there already was another thread hiding.