Yes, basically it means "doesn't look very good"

It means that he/she is pessimistic about that

when u are going to do something, I say 我看好你 to u. It means I think u can finish this successfully. when something in which exists some argument(yes / no) is going to happen, I say 我不看好 something, it means in my opinion, I think it is going to be "no" in ur example, 现在很多国家让同性恋合法了，同性恋者的权益理应受到法律保护，但我不看好，因为中国.......... It means "......I dont think China will allow the homosex to be legal because......."

it is supposed to be bad prognosis or not promising 很不看好 我本人可以接受同性恋者但是很不看好 I can accept same sex marriage personally , however, I dont think it can be widespread accept here. 很不看好的內容可再描述一下，因為不看好只是一個粗略的方向，至於是個人不贊成還是立法不容易，哪個方向不看好，就不知道了

It means that although the writer is fine with homesexual, but in China It still won`t be accepted by most of people. And it will bring something bad to society.