They become so bitter usually because they try Second Life, find out how easy it is to have 'hot wild sex' with some 'hot chick'- have their little avatar do so, only to suddenly discover that the person behind that avatar is some fat middle aged guy called Abdul. The trauma makes them so bitter.
SLIer's who have done it MORE than once before they discover that its a man on thee other end (usually by wanting to do voice and therefore HEAR them) can be spotted by the use of the mantra "I at least have a first life"
Please note this line is only used by American and British SL users who do this- as far as we can tell the millions of Brazillian, Turkish, Russian, French, Spanish, Japanese SL users do not use it so much for 'hot sex'.
SL user: You had oral sex with a man using a female avi didn't you?
SLI: He said he loved me... (sobs) People who use SL have no life...
SL user: There there, it will be ok... no need to be a Second Life Insulter...