I'm not extremely fond of S/G myself (I assume you mean Sara/Grissom) but I write short angsty ficlets because I enjoy angst and they are so easy to make angsty. Yes, I think people have nothing better to do than flame authors just because they don't happen to like the pairing. I don't know if it's necessarily age (I know people younger than me who act more mature than some thirty year olds I know) but it's definitely a lack of maturity.