Why is the "Green Party" in every country a far-leftist party?

I have noticed a rather curious pattern about political parties in western countries: Most western countries have a "Green Party" (often named exactly that, in the local language) which in theory is a party whose main driving goal is environmentalism.

However, every single such party I know and have ever heard of is always, always, very far-leftist in their political ideology.

They are always the strongest supporters of leftist policies, including unrestricted mass immigration, fighting "racism" (which in practice means "non-far-leftism") by creating stricter and stricter unconstitutional laws, varying degrees of socialism (if not outright communism), "trans rights", and all the buzzwords and talking points of far-leftist intersectional social justice warriors.

Always. I do not know of a single exception, in any country.

In fact, their far-leftist "social justice" policies are most often, if not always, way more important to them and by far their primary talking points than environmentalism. You know, the very reason that the party supposedly exists.

But I have wonder: Why? Why does this seem to be universal? Why does "Green Party" always equate with "far-leftist party"?

There's nothing inherently leftist in environmentalism. I see absolutely no problem in a primarily environmentalism-advocating political party being very centrist, or even very conservative. (In fact, it would actually make even more sense for an environmentalist political party to be conservative because, among many other things, unrestricted mass immigration of people doesn't exactly help the environment.)

So why isn't even one single "Green Party" in any country even just centrist, not to talk about being outright conservative?

The more I think about this, the stranger it becomes.