I think my bisexual friend has something in common with the bisexual kid at my school.
What is the common factor you think that you are seeing?
The kid is an alcoholic and has a gambling problem, so my friend must be the same.
Just because one person has these problems, doesn't mean someone else does. Them having the same sexual orientation does not mean they are the same in other respects.
How are you so sure about that? I thought this was the case.
It is not the case. People are different based on their experiences. One shared trait does not mean they have others.