This is a long reply, but understand that I don’t intend a mean tone here, I am just speaking my honest thoughts in response to your question.

When I was on reddit I wasn’t exposed to so many people with extreme absolutist views

You have entered a place with many groups of people with many views, and you are paying attention to the loudest ones. I can understand that can be upsetting to someone if they haven’t spent a lot of time outside of reddit. Surely on Twitter you would have seen more of this kind of thing, but it really depends on what and who you pay attention to. In my case, people always talked about how volatile Twitter was, but that was never my experience, because I was on it strictly to follow various artists. I just ignored everything else, or otherwise often just didn’t bother myself with other people’s thoughts on there.

who will stop at nothing to maintain the echo chamber.

Lemmy, functionally, is a collection of echo chambers, and chambers of many other kinds depending on how you leverage it. Some - often the loudest - do devoutly believe in the things they believe in and will talk about it all the time.

Reddit was/is arguably a single large echo chamber, but you may have not noticed this because that chamber aligned with your personal thoughts and opinions.

What you are describing sounds more like someone who has left an echo chamber with a set of strong ideals and entered a place with many multiple strong ideals rather than someone who has entered one, as your chief complaint sounds like you don’t enjoy that there are multiple groups of people who believe in different things than you as strongly as you believe in what you do.

Very few people here are able to make concessions.

What concessions do you want, or think are necessary? You have the options of blocking the communities or people you disagree with, or creating an account on an instance which defederates the instance/s you primarily disagree with and/or has rules for its communities that you identify with. You can also install an extension and filter stuff based on keywords:

https://greasyfork.org/en/scripts/471718-lemmy-post-keyword-filter

If what you want instead is simply for most other people to believe in what you believe then unfortunately I just don’t think that’s a realistic expectation to have for the international public.

I just feel like every time I get on here I go away angrier.

Well, you can try the above things to ignore the things that make you angry, otherwise I spent my first year on Lemmy working on tolerating and contending with the thoughts of people other than me instead - of course I have blocked some communities and some people as I agree some are more trouble for me than I find worth in, but generally speaking I think forcing myself to learn to control my own feelings when I see a complete stranger say something I personally disagree with has made me a more patient and better rounded person.

Personally, if someone says something I disagree with, that is just how the world is, and I know this is the experience of every person on the planet to some degree, so I have no expectation that my thoughts and feelings are special to anyone else.

It is just is not possible for every single person to be in agreement on every single thing, so it is useless for me to be mad about other people’s thoughts. Sometimes, I think it is useful however, to express your reasoning to other people, even if some of them hate you for it and even if you feel it’s at your own expense because otherwise how would anything work socially between anyone in the world. But even at that, I don’t think I ever feel the obligation to.

I have learned that for my peace of mind, there is a line to walk such that I never feel my opinions or feelings are innately righteous, and that they are not pointless either. I find believing this about other people’s thoughts and feelings as well helps me to meditate on why people think and feel the things they do; to reach an understanding of those things even if I disagree with them.

We won’t attract new users if we’re like this

I have a contention with this for a couple reasons.

I think that if the objective of Lemmy as a platform were user count, it would be a business instead of software, and I am glad it is not a business. That is what attracted me to it, and I am not too concerned if other people aren’t. Lemmy probably will never attract a lot of people like normal social media, because it isn’t a business and has no marketing as a result. In some ways I think Lemmy could even be made worse by having a population like reddit or twitter.

The idea of “we” is unclear here compared to traditional social media. Do you mean “we” the users on the instance, “we” as in all users on all Lemmy instances, “we” all users on all activitypub based social media platforms?

Depending on what you mean, “we” could both care and not care about attracting more users, and want to or not want to work toward that, at the same time, because it depends on what and who you actually mean.

You’re posting to a community in Lemmy.ml so I have some guesses about what you might mean, but Lemmy.ml is not Lemmy, and many users on it do not hold ideals similar to reddit users in the slightest. Remember, “Lemmy” is just the software.

So the question “is Lemmy worse than Reddit/Twitter” is like saying “Is Firefox worse than Facebook”, though I know this is not what you meant.

My answer to your actual question as a result is Yes and No, at the same time, because it depends on which instance you are on, which instance you are looking at, if you leverage the blocking and filtering available to you, and your ability to contend with people who are different than you.