I agree with all of your major points throughout this article. But it works the other way too, as Ann just stated elsewhere in this thread: there are many bisexual people out there who insist/claim that EVERYONE is inherently bisexual (or pansexual), just at different points along the spectrum.
That "opinion" is blatantly exclusive of 100% gay and 100% straight people out there.
Why can't we all just accept the breadth of the sexuality spectrum as it is? -- that some people are either mostly/exclusively attracted to the opposite sex, some people are mostly/exclusively attracted to the same sex, and a whole lot of people in the middle are attracted to both sexes, to various degrees...many of them being fluid in how their attraction works.