That’s not what they said though. They were clearly meaning that tone and context are the difference between “my sister is gay” [neutral], “my sister is gay” [negative], and even “my sister is gay” [positive].

“The wedding i went to last weekend was gay” could mean two people of the same gender got married or it could mean that someone is mad that a man dressed nice and was involved in the planning of his wedding and you can usually tell based on tone.