IMO the title of this blog post was way to strong to even misleading.
They're not asking for deplatforming, they're asking for more transparency:
Reveal who is paying for advertisements, how much they are paying and who is being targeted.
Commit to meaningful transparency of platform algorithms so we know how and what content is being amplified, to whom, and the associated impact.
Turn on by default the tools to amplify factual voices over disinformation.
Work with independent researchers to facilitate in-depth studies of the platforms’ impact on people and our societies, and what we can do to improve things.
I disagree with your assessment. I will illustrate why by using 2 specific points from the linked post:
1. From the post: "Changing these dangerous dynamics requires more than just the temporary silencing or permanent removal of bad actors from social media platforms.
Additional precise and specific actions must also be taken: [...]"
My interpretation of the above is that they support deplatforming ("silencing or permanent removal") AND "additional actions".
2. They mention "white supremacy". I believe that is a false premise. I am not white/of European descent. I will leave it at that since this is going OT.
They're not asking for deplatforming, they're asking for more transparency:
Reveal who is paying for advertisements, how much they are paying and who is being targeted.
Commit to meaningful transparency of platform algorithms so we know how and what content is being amplified, to whom, and the associated impact.
Turn on by default the tools to amplify factual voices over disinformation.
Work with independent researchers to facilitate in-depth studies of the platforms’ impact on people and our societies, and what we can do to improve things.