So this is a discussion I came across on Reddit...it's kinda too long for here so I've tried to keep in the main points. For those non gay people who think it's 'trendy' to go to a gay bar, or like to pat themselves on the back for doing it, maybe think twice...
One thing you have to consider is that if you're straight, you have the luxury of being able to safely assume everyone around you is straight unless someone indicates otherwise. Gay people don't have the equivalent luxury.
Keep in mind that if you're a straight person going to a gay bar, you make it harder for the LGB patrons to find potential partners. After all, if enough straight people go to a gay bar, it's no longer a gay bar, and the local gays/lesbians may have no where they can safely hit on others of the same sex.
Consider a gay guy who goes on a ski trip in a group of 160 people. Educated estimates for LGBT people are about 5% of the population, so that means probably about 8 people in the group are gay or bi. Now image that you wanted to do what straight people often do, meet someone, hang out, maybe even have some sexy-time. Half of those 8 will be women, and only half will be single. So that brings it down to 2 single gay guys including yourself in the entire group.
The odds are astronomically stacked against you and the other single gay guy meeting each other and knowing that each other are gay. After all, there is no magical way of determining which of the 159 others is gay, and there are often severe penalties for guessing if someone is gay. On top of all that, you have all the typical issues with finding a partner that straight people face. So even if you manage to identify the one other single gay gay, you very well might not be each other's type.
On the other hand, if you're straight, all these extra barriers are removed. Although they might not be interested in you for other reasons, you can safely assume that others are attracted to the opposite-sex.
Statistics show that the majority of straight people meet their SO randomly (friends of friends, work, etc.), which works because straight people have the luxury of being able to assume that each other are straight.
...I don't think it's intrinsically wrong for a straight person to go to a gay bar. But unless the straight person is going as a wingman/woman for his/her LGB friend, I think it would be very inconsiderate to not at least seriously think about going somewhere first."