Section 230 is NOT "Law" in the classic American tradition of prohibiting specific actions

But it does prohibit a specific action — specifically, the act of suing a person or company for the actions of a third party. Under 230, someone can’t sue Twitter for defamation if a third party posted (allegedly) defamatory content without Twitter’s direct knowledge or aid.

the text only says react to "restrict access to or availability of material"

You put the actual text in your post, yet you still have the audacity to lie about it in your next sentence. The text of the law says nothing about “reacting”; any action, proactive or reactive, counts. A Mastodon instance that bans the use of, say, a racial slur and filters it out before someone’s post goes through is a proactive measure that is 100% allowed under 230.

it doesn’t authorize "a priori" withholding of all "service" to "natural" persons for arbitrary or no reason

No law exists that allows someone to force their way onto a privately-owned third party platform and use it for their own speech. Banning someone who breaks the rules is an “action voluntarily taken in good faith” to keep the platform from being overrun by rulebreaking content. That is as true for Twitter as it is for, say, some kind of family-friendly forum.

It’s not even a step change, because once dropped "constitutionally protected" there’s no limit!

Which is exactly the point of “constitutionally protected”: We recognize that discrimination based on inherent traits (or their chosen religious creed) is bullshit. You can choose to be Republican or Democrat. You can choose to act like an asshole. You can’t choose to be gay, which is why people shouldn’t have to face discrimination based on sexual orientation — and yes, that includes straight people.

Masnick simply DELETED the "in good faith" requirement!

And as he explained: “[T]he courts have made it clear that ‘good faith’ means ‘whatever the platform wants’. And, as you know, ‘common law’ actually means what the courts say about the law, and so — you’ll love this — under the common law you insist is so important, ‘good faith’ means as long as the platform has a reason to moderate your bullshit content, that’s clearly allowed.”

How did those characters get removed from the middle of a quote?

He used either the Delete key or the Backspace key.

show intent of legislators besides who’s to benefit

Let’s go to the legistlator himself, then:

We want to encourage people like Prodigy, like CompuServe, like America Online, like the new Microsoft network, to do everything possible for us, the customer, to help us control, at the portals of our computer, at the front door of our house, what comes in and what our children see.

…

[O]ur amendment will do two basic things: First, it will protect computer Good Samaritans, online service providers, anyone who provides a front end to the Internet, let us say, who takes steps to screen indecency and offensive material for their customers. It will protect them from taking on liability such as occurred in the Prodigy case in New York that they should not face for helping us and for helping us solve this problem. Second, it will establish as the policy of the United States that we do not wish to have content regulation by the Federal Government of what is on the Internet, that we do not wish to have a Federal Computer Commission with an army of bureaucrats regulating the Internet because frankly the Internet has grown up to be what it is without that kind of help from the Government. In this fashion we can encourage what is right now the most energetic technological revolution that any of us has ever witnessed. We can make it better. We can make sure that it operates more quickly to solve our problem of keeping pornography away from our kids, keeping offensive material away from our kids, and I am very excited about it.

Those are the words of Chris Cox, the legislator who co-drafted what would become 47 U.S.C. § 230. You can even read them yourself; they’re on the Congressional record.

why were they removed except to try and affect the argument?

Because, as Mike explaned, the words are effectively meaningless in the context of this argument. So long as a platform can offer a reason for their moderation decisions, the courts consider those decisions to have been made “in good faith”.

It’s New World Order fascism.

No, fascism is the United States federal government telling a company like Twitter that the law will force it to host all speech, no matter what, and any attempt to moderate speech will result in legal and financial punishments. Fascism is the government saying Twitter must associate with White supremacists and other such scum because to “disassociate” (read: ban) such people from the platform is also an illegal attempt to moderate speech. If you think Twitter banning an asshole from the platform for being an asshole is fascism, you have proven how far out of your depth you are in this argument.