What's wrong with "don't ask, don't tell"?

In addition to some other institutions, most famously the United States military forces had for really long a semi-official "don't ask, don't tell" policy, meaning that if you are a homosexual that's fine, nobody's going to ask, nobody's going to discriminate, but it's better if you just keep it to yourself as well. What you don't know can't hurt you and, more relevantly in this case, what nobody knows can't hurt you. There will be no prejudice nor differential treatment (positive or negative) if nobody knows you are "different".

Famously, this policy was officially ended recently. Apparently the "don't ask, don't tell" policy was considered oppressive, I suppose?

But I have to ask: What's wrong with it? I'm asking 100% seriously. Why is it wrong to have such a "don't ask, don't tell" policy?

Why would people want to go around telling other people, unprompted, that they are homosexual? What for? People don't usually go around telling that they are heterosexual. Do you go around telling random people, or coworkers, or whoever, "hey, did you know that I'm heterosexual/homosexual"? People don't usually do that normally.

There may be some people, including (and perhaps especially) in the military who are prejudiced against homosexuals. Maybe their attitude would change, or their trust, or their amicability and loyalty, maybe they'll become distant or perhaps outright hostile, maybe they'll start teasing or even bullying. Some people are a bit of assholes that way.

But, as said, if they don't know, they won't do it. So why explicitly go ahead and make them know? Is that the whole idea? Make homosexuals "come out" and reveal themselves, and make the prejudiced people likewise reveal themselves, in order to punish them?

Of course that's not what happens. People, even assholes, are smarter than that. If they see what's going on, they will just shut up and hide their disgust, mistrust or prejudice.

The problem with this is that now there's more hidden distrust and antipathy among the soldiers. There may form subtle divisions between the troops, where some soldiers become more distant from others, less trusting, more hesitant to cooperate and work together in camaraderie and good spirit. The prejudice will not go away by triggering it and pressuring it to be hidden, bottled up, building up on the inside.

A "don't ask, don't tell" policy avoids all that. Who does it hurt, exactly? Does the average homosexual really have the irresistible urge to reveal his preferences and tendencies? Does he crave it so much that he suffers every day that he can't blurt it out? Is it like Tourette's, but instead of having the urge of blurting out swearwords, he has the urge of blurting out that he's a homosexual?

I don't think so.

So, who does "don't ask, don't tell" hurt, exactly? If it ensures camaraderie, cohesion and friendship among the troops, what's the harm?