I think that the reason you see angry takes here, is that here on Tumblr, we are all on a more equal footing. You might see some really ugly language here because here it is safe to say it, and for the most part, I don't think people really mean it, but they are angry because of how they have been treated and blowing off steam. Think about it, do you hear LGBTQ+ people saying those things in real life or do you only see it online? Do you hear women saying those things irl, or only online? Why might you only see these ultra angry takes on the internet in more anonymous places? Do you think it might be venting just like you're doing right now?
By saying LGBTQ+ rights matter, I am not saying that straight rights do not. But in real life, we are not on equal footing. If I got engaged to someone of the opposite gender, I could go and tell my coworkers about it and they would be happy for me. If I get engaged to someone of the opposite gender, honestly? I'll probably start looking for other work. I fully expect a truly ugly backlash that will push me out of my job if I ever get serious enough about someone to marry them because I work in an area where: 1. I work with kids. People seriously think that queer people corrupt kids/are perverts. 2. Where I work is right to work. They can fire me and never have to tell me why. If enough people complain, it doesn't matter how good I am at my job, I'm not worth keeping around. 3. As someone who is not out at work, I get to hear allllll the nice totally progressive and not horrible opinions of my coworkers. And my thing? I can choose to hide it. You can't hide skin tone. Also, just think about what it would feel like to have to hide a major part of who you are all the time or be ostracized from everyone you talk to on a regular basis. Deadass I pretend to be someone I'm not for about 70% of my day. Just a huge chunk of who I am is considered so wrong that I can't talk about people like me at work. I can't give the kids an example of someone like themselves as part of the lesson, I have to sneak it in on the sides, quietly.
I work in an area where I see a lot of t-shirts that say things like thin blue lines, all lives matter, and I stand for the flag. But what I think people fail to realize is that when black people are having to loudly proclaim that their life matters, it's because there are a lot of people who think that they don't. My area is largely white, so the people wearing these shirts aren't meeting a lot of black people, but they do know that when they see "black lives matter" they take it to mean that their lives don't or that they couldn't possibly be also struggling. But if you don't have a hiring barrier based on your skin tone, I don't need to fight for anti-discrimination policies for you. If black people are marching because they're being shot and terrorized by the police or their own suspicious neighbors and you walk up and say, hey, I don't understand, why are you saying black lives matter? Why can't we all just get along? That's pretty tone-deaf. Hey, I see that another unarmed black person got shot, but it hurts my feelings that I'm not included in the group you're championing right now.
Don't get me wrong, I think it's normal to have the knee-jerk reaction of, wait a second, are you saying that -only- x group matters? But, it's our job as citizens of the world to constantly reexamine our thinking and see if we're missing something. But, and I say this as gently as I can, if you're not experiencing the problem, it may be hard to understand why people are upset, and why when you walk up, they don't rush to make you feel comfortable.
I don't always agree with the rhetoric either, sometimes it makes me uncomfortable, but at that point it's up to me to decide whether or not I'm uncomfortable because what I'm seeing is challenging something I've never had to think about, or because it's gone a little too far over into hate territory, at which point I just usually let it pass because again, we're on the internet. Let me be clear the only point at which I usually feel people are going too far is the whole, oh, all men are terrible thing. That's not true and it can give people a weird complex about themselves or let people excuse bad behavior. "Well, if I can't be good at all, why bother?" kind of thing.
In parting, let me offer you some advice someone offered me a long time ago when I asked a question like yours. If you don't understand why people are on the opposite side of you on an argument, find out what their actual reasons are for doing something, not what your side says is their reason. Most people are not cartoon villains who do bad things just to do bad, they believe they are in the right.