"Virtue signal" is a bad-faith term that means nothing other than its use as a cheap dismissal from people refusing to engage with the content of text, even short text like this. It's not a serious analysis, or a criticism of anything at all.
> "We support free speech, unless it's speech we disagree with"
Notably, you are using quotes around something that is not a quote. Your interpretation of the text does not flow from the content of the text. Tor's stance is the bog-standard pro free-speech stance, as Hall wrote in characterization of Voltaire, "I disapprove of what you say, but I will defend to the death your right to say it".
Here's an actual quote from the text. This is the _second sentence_.
> We are not terminating the relationship but are setting clear boundaries on our relationship with Mullvad.
It is clear that you did not even read the text of the short post you are dismissing as "virtue signaling"!
Tor is actually still collaborating with Mullvad and they are no longer "co-branding". They are releasing a statement of their position, which is normal, necessary, and expected.
They clarify that Tor is a political project. Security and privacy are human rights goals which necessarily contend with the political context of surveillance and authoritarianism they exist in. The co-founders support of a far-right party, and the implicit support for surveillance that comes with it, are of significant and immediate concern to those who use Tor and Mullvad.
I mean it's not clear how its supposed to be anything other than virtue signally.
The claim that an expressed belief is principally a kind of signalling means that its content isn't a sincerely held belief by anyone, but the act of expressing such belief serves to signal to some audience a certain non-propositional kind of information. Virtue signalling is a signalling to indicate virtue, and in many practical cases is taken to include tribal loyalty to a particular political project.
Jesus used the phrase, iirc, "praying in the streets":
> And when you pray, do not be like the hypocrites, for they love to pray standing in the synagogues and on the street corners to be seen by others
The observation that behaviour signals virtue is as old as the species itself.
Protestations to caring about human rights are, often enough, a modern sort of liberal prayer, practiced in the street or the public internet. And one imagines a vast amount of corp speech exists for signalling purposes (if not virtue,, then eg., to signal strength or growth, or trust). This entire posts exists to signal, it's unclear it expresses any sincere belief whatsoever.