NJ
You posted:
//All the pubs I’ve ever used (and I’ve been in a few!) have been “gay friendly”. I have never been into a pub where gay people have been unwelcome or treated any differently to straight people.//
Can you explain how you know this?
Have you been to a pub where your many gay friends have kissed, and no-one has made a comment?
You also wrote:
//Of course that could be because few people, except perhaps the friends that they are with, would know the sexuality of any of the customers. The gay friends that I have no more demonstrate their sexuality when in a pub than I do.//
That's the point. In gay bars, you can chat up people in the (fairly) sure knowledge that you're not barking up the wrong tree. I assure you that the gay friend you do have would not demonstrate their sexuality in straight bars, because there's literally no point.
You then say:
//What is really meant by a “gay friendly” bar is one frequented exclusively by gay people who exhibit considerably different behaviour to most people (straight or gay).//
Nonsense. Gay friendly bars are rarely exclusively gay.
Go to any gay friendly establishment in Brighton or Manchester or London and you will see that they are NEVER exclusively gay. This is because unlike in the past, gay people have straight friends who go to gay bars with them. What you may be thinking of are gay bars from the past. It's not like that now. I understand why you may think that, but you're wrong.