> Effectively, the judge makes it impossible for X to defend itself in court because he'll just have anyone arrested who tries.
No, on two counts.
First, Twitter is free to seek out a lawyer to represent them in court. Most people hire lawyers for contract work rather than as a permanent employee, so this remains possible even with no assets within Brazil.
Second, there was nothing to be defended until they refused to comply with the lawfully given order within the required deadline.
That they chose to fire their staff member and close the office in order to prevent compliance with the lawfully given order, was an actual offence in its own right. To my limited understanding, it is also an offence in its own right to refuse a lawfully given court order. But in both cases, Twitter was not being punished until they actually broke the law.
Courts in the UK and the USA may issue an injunction, both to prohibit and/or to compel an action, and this may bind on people not directly before the court:
https://en.wikipedia.org/wiki/Injunction (note in particular that interim injunctions may be given prior to a ruling on the case itself)
https://en.wikipedia.org/wiki/Injunctions_in_English_law
https://en.wikipedia.org/wiki/Interim_order
https://en.wikipedia.org/wiki/Quia_timet
And, pertinently to Starlink: https://en.wikipedia.org/wiki/Asset_freezing
Compare and contrast Twitter in Brazil with Lavabit in the USA: Lavabit was ordered to provide certain information in secret (with an injunction to not talk about it); they protested, they first provided that information in an obtuse form that was considered contempt, they provided it in a form which was acceptable, then they closed their business in response and took further legal action in response to what they — and, to be clear, I — consider to have been a manner incompatible with the public view of American Democracy:
"""Levison said that he could be arrested for closing the site instead of releasing the information, and it was reported that the federal prosecutor's office had sent Levison's lawyer an email to that effect."""
and
"""Levison wrote that after being contacted by the FBI, he was subpoenaed to appear in federal court, and was forced to appear without legal representation because it was served on such short notice; in addition, as a third party, he had no right to representation, and was not allowed to ask anyone who was not an attorney to help find him one. He also wrote that in addition to being denied a hearing about the warrant to obtain Lavabit's user information, he was held in contempt of court. The appellate court denied his appeal due to no objection, however, he wrote that because there had been no hearing, no objection could have been raised. His contempt of court charge was also upheld on the ground that it was not disputed; similarly, he was unable to dispute the charge because there had been no hearing to do it in."""