

does your language assume that gay people do not exist?
pretty much. Many old folks consider it as a disease or mental illness.
Do you use the exact same word for a man who likes women (eg a straight man) as you would for a woman who likes women (eg a lesbian)?
That was not a thing, and hence it never had a word/s. basically someone born with a male reproductive part was male, other is female, and that is about it. A male was (is) expected to marry a female (love or arranged(where family finds “suitable” partners, and the bride/groom have little idea of other)).
Things have changed a lot for better in past 2 decades, but much of the “older ways” still remain as “traditions”.
I never confused sex and gender, as you describe them, as I said these do not exist as separate concepts in my natiive tounge. I used different words for them, which while not ideal, do convey the meaning. My questions were mostly regarding gendered pronouns, and having terms for different sexes (as in lgb of lgbt) or genders (t of lgbt), and why do even need terms for these, or why would one like to share it with others.
I would not give you a specific language, but country is India
this is new to me. In my post I used orientation for what I assumed to be gender, but I had no idea it was also related to attraction.
I do understand both points of finding similar folks or possibly finding partners