Oftentimes the role of “What is your favorite X?” is a conversation-starter. I think it’s perfectly honest to interpret “What’s your favorite kind of music?” as “What’s a kind of music that you like and which you’re willing to have a conversation about?”.
An exception is “What’s your favorite superhero?”, because you may be called on to defend your choice in an argument.
Oftentimes the role of “What is your favorite X?” is a conversation-starter. I think it’s perfectly honest to interpret “What’s your favorite kind of music?” as “What’s a kind of music that you like and which you’re willing to have a conversation about?”.
An exception is “What’s your favorite superhero?”, because you may be called on to defend your choice in an argument.
this is sometimes the case, but there are enough exceptions that one should not rely on it I think.