I think there are two things at play here: Representation and skill.
The people that want people like them represented often don't even want the representation to be the focal point of the character. They want a well-written character that just happens to share this thing with them which makes them a minority. They don't want a token character that's just in there for the quota.
And that is where a lot of media falls flat, IMO. They somehow slap a minority character in there but then they center everything around that or they pile identity onto identity. I remember a book I read, like, two years ago where the love interest oh-so-happened to be a black, demisexual, gay trans man who was practicing a minority religion as well. It came up once, the guy felt about as flat as cardboard to me, and I genuinely felt that the book was lacking in almost every aspect that would have been important to me. It would have made sense to focus on his religion, for example, because the setting had to do with religion (which finally didn't happen though as far as I remember, there were hardly any details shown and it had no real impact on the plot). The rest? Well, nice, but it just felt like too much.
I'm not even saying that kind of thing couldn't happen but, let's be honest, the combination would certainly be rare and there just comes a point where I can't help but roll my eyes. It's the same if a character somehow is a gifted concert pianist who hacks the government in their free time, goes mountain climbing when they're on vacation while phoning their president for the secret mission about some drug smuggler ring that they're going to take down with their awesome karate skills. Yeah, you can write that but I'll just feel like I would have liked the story to have some center, some consistency in where it wanted to go (unless it's a comedy, I can forgive comedies almost everything). And it becomes so much worse if half of that stuff is only mentioned once but never really shown. - That's just bad writing though.
Personally, I am part of a minority group myself. Growing up, I didn't know though. There wasn't a single movie or series that I saw, not a single book I read that had characters like me. Education on LGBT+ matters was non-existent when I went to school as well so I was left with just feeling like I didn't quite fit in until I kinda stumbled upon things in my mid-twenties. It was a relief when I found out and from conversations I had with other people and what I've seen others share online, I know I'm not the only one feeling that way.
And this is why I think that representation is actually important because it can show people that they are not alone in whatever they are experiencing because of their identity. We don't need to be in every show. We don't even need to be in every second or tenth one. We don't need to be the main characters either. But people shouldn't have to go through twenty years of watching and reading stuff without ever having the opportunity to come upon a person like them in at least a half-popular show or book. Just give us that one random side character that appears every now and then and whose orientation you'll bring up when it's relevant to the plot. (Which is easy, btw, any sexual orientation can simply be brought up in regard to dating questions or by introducing an SO, anything like that. It's not rocket science.)
Because of my own experiences, I do include minority characters in my stories. I mean, I'm writing gay romance so maybe no surprise there but I also try to include characters of other identities. It's a one-on-one basis thing though. I have two slots per year for a story where a character of my own orientation will be the main focus. Right now, their orientation is actually an important part of the plot but I might tone that down in the future (only started it in 2019 so right now, I want to explore some of the more closely-related stuff). For the rest of the year, my characters are usually just gay or maybe bi (because, again: gay romance, so kinda the prerequisite).
Every now and then, there are side characters with other orientations and that especially happens when there is a huge cast. Like, it's just a numbers game. If I have a cast with just five people, the main couple will be gay and the rest will be straight because that just makes sense. I think studies said up to 10% of men are gay/interested in men with the numbers likely being slightly lower actually? If I have a long story that spans several volumes and will thus have a bigger cast with maybe ten people or so already being the core while there will be maybe 20 more characters that regularly appear throughout the story but don't take the center stage for long and then having other characters that don't appear often but might be important in one arc or two before they vanish completely, then yeah, you bet there will be two or three characters of a different orientation among them. That's just how it'd be in real life as well.