I don't recall saying homophobia doesn't exist?
I never said you, personally, did. You are one person on this thread.
I'd genuinely like to know how often revealing you're not straight (coming out) has led to homophobia?
In my experience, roughly 15% of the time. And I have spent my whole life living in either London or Brighton, so therefore will have experienced a lot less homophobia than many others.
Or is it the fear of a homophobic response, in the same way a lone woman might fear a random man?
Yes, the fear is always there because of the aforementioned homophobia.
Does homophobia in this case, also include people assuming you're straight?
No, it does not.
And does it include people like me not wanting to be forced to go to Pride events by their employer?
No, it does not.
Are you saying homophobia - people actually hating on people because of same sex orientation - is as common today as it was 40 years ago?
No, I am not- you have completely plucked that out of nowhere. What I am saying is that homophobia absolutely does still exist, and that straight people have no business telling gay people that it doesn't.
I'm so glad I am able to clarify things for you.