When you said "this is so gay", without context, people will assume you meant it in a negative way. This is because that term has been thrown around in our society as a negative term for a long time. That word, and worse ones, have been used to discriminate against said people for a long time, and thats why this rule exists.
As for those other words, very seldomly do you see them used in any sentence, and in a negative matter.
It doesn't matter if you, or your friends are homosexual, the rules are meant to appease to a whole audience of players. Getting rid of this of this rule would make the servers a lot less enjoyable in my eyes.
Protip; stay away from potentially controversial words, and you'll be fine.