Answer:
As the world "queer" mainly means in a sense of "strange character or strange vibe/feeling", So, in some regards it is also termed as very offensive in nature for a person to hear for himself.
Explanation:
From the past 20 years the word "queer" is mostly used for a a person who is gay, lesbian or more over transgender in nature. So, the word queer is used in a more insulting sense by a person just because it has the sense of referring a person to be very strange in nature.