"the thread is about study of emotions on earth, of which sexual longing is very primal, giving rise to, for example, the jealousy then anger to propel Cain to kill his brother or giving rise to regrets"
Oh, so what sexual longing and jealousy caused Cain to kill Abel? I'll accept it was a kind of jealousy but I fail to see where sexual desire comes into it.
"so, back on topic, to you really believe beings reproduce just to be like everyone else? "
Your question was related specifically to the text about Lots daughters, and that was THEIR motivation. It makes no comment on the motivation of others.
"further, if they do actually want to be like everyone else, what exactly is this emotion of "wanting"?"
The desire that exists when you believe that there is something out there that you need but don't have. "Though shall not covet" etc. Or in Buddhist language it is the 'desire' that brings suffering.
