Don’t be like that. We’re all discussing in good faith here.

It's not good faith to misrepresent or outright fabricate events. Nor is it good faith to dismiss people who are trying to point that out to you. There were no such lengthy, anguished conversations or multi-episode arcs. I'm baffled how you fabricated entire scenes that never occurred?

Adira spends considerable time with the ghost boyfriend on how would that be received and goes through considerable angst processing it. Before even that it’s shown them in considerable anguish to come out to their boyfriend even.

That never happened. That 90 second clip is it, and it's actually only 27 seconds of that scene. It was never brought up before or after that conversation. Remember, Adira had amnesia when we first met them and was unable to recall anything about their past.

Of that arc, the one thing well executed was the 90 seconds you pointed.

There was no arc. That clip comprises the entirety of Adira's coming out. Not to be redundant, but it's never discussed before or after this scene.

So yeah, most of it shouldn’t happen in a welcoming environment in the 25th century. Her adoptive parents had no issue being a gay couple adopting a teenager,

You misgendered Adira and got the century wrong. Stamets is from the 23rd and Adira is from the 32nd.

Your comment is a moot point because Adira never once says they were discriminated against or fearful of that happening with Stamets (or any of the DIS crew.)

Setting that aside, in general you cannot make blanket statements about individuals unless they're the Borg. People aren't deterministic machines who follow a static program they're unable to deviate from. They all have have different life experiences, cultural background, beliefs, and personalities which result in different levels of enlightenment. It would be more accurate to say that discrimination still exists in the future but it's less likely relative to modern times.

There's plenty of Star Trek episodes that demonstrates discrimination still exists. The Federation and Starfleet discriminate against synthetic life. Data was treated as property and ordered to undergo a life threatening procedure so Stafleet could create a race of slaves. He had to sue in court to win the right to choose is own fate. The Doctor on Voyager had similar experiences. Picard discusses the undercurrent of discriminatory attitudes that hampered the Romulan evacuation effort in PIC. Shapeshifters are often treated in a prejudiced manner and viewed as untrustworthy. Barclay was treated poorly by the Enterprise crew for the crime of not fitting in.

People in the future of Star Trek are still imperfect. They're fallible beings who can engage in irrational behavior like discrimination. A more accurate statement is that discrimination still exists, but it's less likely. Such things work based on probability, and the role enlightenment plays is to make it less common. Outliers exist though, especially in a population numbering in the trillions. All it takes is one bad experience to shape Adira's interactions with others.

Anyway, this pretty much a moot point because Adira never mentions being discriminated against or felling that might happen with the DIS crew.

She

You misgendered Adira again.

doesn’t come from a backwards culture, has crazy conservative parents, there’s no atavic crewmate around, no aliens taking offense

No, you don't actually know this. Those elements of Adira life are never revealed. Adira never states they were discriminated against or feared that's what would happen on DIS. I'm unsure where you're getting this.

If you're referring to their tone or body language, you'd have to be psychic to know it was specifically a result of discrimination. There are lots of logical explanations you're dismissing such as the simplest one—Adira's personality. Conflict of any type (such as correcting your abrasive superior) often makes people uncomfortable. Occam's razor and all that.

Even if I give you the benefit of the doubt I see no problem with that scene. Maybe Adira assumes someone from nearly 1000 years in the past is a bigot? Imagine coming out to someone from 1123. Or maybe Adira did have unaccepting parents or just one single bad experience that overshadowed everything? How do you know more about Adira's life than Adira themself? That's not a good faith argument; that's just confirmation bias.