is it unfair to make things better for some when the majority is paying to keep the game as it was before?

As I already said I think, yes it is unfair.

However, you really have to differentiate a bit here, because all the things you talk about that are changing in OSRS seem like they're entirely ignorable. If there's a gay pride event, yeah it doesn't need to be there, but you can also just not participate in it. If it's possible to change your character's gender and appearance, you can simply not do it.

There is no core game mechanic being changed or even tangentially touched. So yeah, it's unfair that they change it when the promise is to not change anything, but it's really also an incredibly small change that has a minimal if not non-existent impact to the majority, but a very huge impact to a small amount of people. At that point it becomes a bit more grey what "should" be done.

almost universally disliked update, I cannot find one positive comment towards it

In the video you added this statement to, there are maybe like 10% of YouTube comments that say they're fine with it. So you saying "I cannot find one positive comment towards it" is a little weird. This is also imo a high amount of positive comments even if it's just like 10% because the 10k views it has will probably mostly be watched by people looking for the controversy and speak their dissent.

protest with a very small amount of people counter protesting

If the red icons are protestors, and the blue hearts are the counter-protestors (which is what it looks like to me) then it looks more like 60/40, which I wouldn't call a very small amount.

But what you really have to compare is how many people participate in the pride march compared to how many protest, that is the real difference that needs to be measured. I look at this video https://youtu.be/jr1XAa2cx_M and there seems to at least be 20 times as many people as what you showed in your protest video. Which is funnily enough about the 5% minority we talked about xD

For me as an outsider looking in, this seems like exactly the kind of mindset by people opposing these changes that is problematic and they need to change, which is about 50% of the population of the US which I suspect is also reflected in OSRS playerbase. I've spoken with people before that are like this.

They think their opinions are being censored and that is a huge problem and they don't want to see this stuff because it shouldn't be political etc.

These are all completely valid arguments theoretically. Like these are not bad views to hold. But they entirely miss the point because that's what humans do, human minds work by compartmentalizing and by "explaining away" their natural behavior. Humans are an incredibly irrational species that try to, after the fact, explain the irrational behavior with rational sounding explanations.

The natural behavior here is the disgust of gay and trans and queer people. Fear/disgust of the "foreigners" or "people very different from myself" is one of the base human behaviors. The reason they can't ignore these events, even though they are entirely ignorable, is because this disgust reaction is triggered within them. Their automatic compartmentalizing brain then searches for acceptable reasons to dislike it, and comes up with "OSRS was said to never be changed" and "politics shouldn't enter the game". This process in a human mind is entirely automatic and not conscious at all. But the real motivation why they can't ignore it is the disgust/hatred of queer people. But they don't even see that this is what's happening, as I said, this process is entirely automatic.

Everyone, including people that hate queers, has this image in their mind of being good. But hating queers isn't good. So "hating queers" doesn't even consciously enter the mind, even though you can easily see it from their behavior. If they didn't have a problem with queers they'd just ignore these easily ignorable things. But they don't.

And even this mine explanation will be vehemently denied by these people. Because that would be too painful, because they would be admitting they're not the wonderful people whose image they have in their minds. Doing this would break them. So they continue consciously saying "of course we don't hate the gays" while subconsciously still hating the gays. And I completely understand this behavior because I was exactly the same at some point. I personally was mysoginistic and racist against immigrants at one point in my life and completely oblivious about it. At the time, I didn't think that I was. But I had all these little unconscious behaviors that showed my true subconscious beliefs. I know how painful it is to confront yourself being terrible. It is not possible to bear this pain for most if your life is already mostly miserable. I was lucky in that I had a relatively good life and a strong self-improvement mindset instilled from my environment, and thus was able to face and bear this pain and effect real change within me. But it was real pain, and had I been in a slightly worse situation, I might have not been able to do this.

What people are doing with pride events and these trans-inclusive changes is yes, forcing diversity down people's throats. You could say that it's wrong to do that to people, entirely true, it is authoritan of them. But the goal is to reduce hatred of queer people. There's just no way you can really argue against these motivations. A gay pride event hurts nobody. No one is forced to participate. They're forced to see it, yes, because studies have shown that exposure to different cultures and lifestyles increases acceptance of them. If they were tucked away, that wouldn't happen. And this triggers their disgust. You probably can't change these people, but maybe all the new ones that haven't been tainted to much by disgust of others behaving "differently".

So in the end, I think these changes and events are good even though they don't strictly "belong" in OSRS.