I don't think straight people realize how often they constantly broadcast that they're straight. It doesn't even take a direct question for this whole thing to come up - "now I must awkwardly either present my homosexuality to this person directly or awkwardly dance around the issue."

If you're a gay person who is actively dating or in a long-term relationship, it's honest-to-god SERIOUS effort to avoid coming out. It isn't just like passive "I won't tell anyone." There are CONSTANTLY situations where it would be natural to just be like "Oh yeah me and the husband went skiing once and x happened..." when people are telling casual stories they don't even realize are couple-centric.

The pressure is there no matter what, because the very fact that I have to stop and correct every person I meet at least once and announce to them that I'm a lesbian makes it really awkward, repetitive and stressful. But the pressure especially happens when they're someone you need to have a positive relationship with, such as a coworker, and you're not really sure what they think of gay people yet, and even people who appear to have gay friends etc could have some really weird notions and start making workplace dynamics feel weird. Additionally, since most gay people have a fairly long phase of being totally in the closet in general, it's hard to let go of that instinct that shouts at you "don't let them find out you're a freak!!!!" even when you feel pretty comfortable with your sexuality. You go through this whole thing every time you meet someone new that you're going to see around a lot - new people at work, new people in your social circle etc etc. It's tiring. Personally, I typically don't tell coworkers/classmates right away, but instead wait until they know me as a person, so that they won't make snap first-impression judgments based on prejudices. It just takes so much more energy than it's worth, and it's all because everyone just assumes you're straight until proven otherwise.