My problem arises with the fact that I grew up in a very homophobic environment. I'm personally bi (so most people just take me as straight). Yet, I have homosexual friends with whom I'm very close, so I understand their struggle on a personal level (having gone through some forms of it myself, albeit never as intensely). It is commonplace to make rude comments about someone for being gay (such as implying a gay man is just a wannabe girl or that they're dirty or very sex-focused, which is not at all the case most of the time). Thing is, in my workplace, such conversations will start around me, and people seem to seek validation from me, probably because they've been used to having like-minded people around them.
In a couple occasions, I've actually tried telling these people why their prejudice is wrong. They wouldn't say these things in front of our gay coworker, so I don't understand why I have to endure that passively. Yet, it's often dismissed as "just a joke" or me not knowing any better. I won't go into much depth about their logic, as it seems like there is none. I find it insufferably grating to have to listen to their insulting remarks, yet find it almost as equally infuriating to try and educate them when otherwise poking fun at them is so much easier and everyone else gets a laugh at their expense. So I've come to the conclusion that it's not healthy for my mind to stress too much either educating them or ignoring them. Instead, I want to remove myself from the equation altogether, as effectively and quickly as possible, without causing much hassle. I know this might seem like Mission Impossible, but I no longer care about whether they have prejudiced views or paint stereotypes over every otherwise unique and distinct individual, because of their sexual preference. I've faced similar issues with xenophobic and racist people, but I'm focusing on homophobic people for this question, as it seems rather recurring.
I don't want to take this to HR, as I find it neither necessary nor practical, and I'm admittedly scared they might not take it seriously. I'd also rather not start up arguments in the workplace. They don't know I'm bi and I don't want to be seen as the "other queer". I'm not afraid to stand up for myself, but I'd rather not have that every time someone makes a joke of poor taste.
So I guess my question is: How can I quickly cease, or cut myself from, a conversation of homophobic nature, without driving it further or having to educate people?
While I'm asking about this on the workplace (so I can't just go about ranting/complaining), a more general approach could be welcome for outside-work situations. I am planning on changing jobs, but my current one (front-end web development) is very good compared to what I've had in the past, so I'm not too keen on the quitting approach just yet. For the time being, I'd rather not get answers that suggest I might have to educate them. I understand some of the extent of the problems of ignoring these issues - as explained earlier, but I don't think I'm psychologically able to stand these confrontations too often. If it's relevant, I'm a 24 years old bisexual woman who lives and works in the US.