@asedysled
It just not a term people would use when they want to speak politely about LGBTQ people. At least in America. I can't speak for other English speaking countries because I don't live there.
It's an outdated term usually used by people who want to seem accepting of gays but who are really not all that accepting. Instead of using terms like gay or LGBTQ which are the more commonly used and accepted terms, homosexual, which is extremely outdated, has a negative connotation. Maybe Google it? I'm not sure I'm doing a good job explaining.