I don't understand why you'd be confused after reading the original source[1]. The authors explain at length why they consider it to be Meta's problem, and it's not hard to understand - Meta make misleading claims about their own ability to detect and filter personal information. It also appears the detail sent was a lot less obfuscated than you indicate here.

If you only got as far as the press release[2] then I can understand your view:

> * Tax prep companies shared extraordinarily sensitive personal and financial information with Meta, which used the data for diverse advertising purposes

> TaxAct, H&R Block, and TaxSlayer each revealed, in response to this Congressional inquiry, that they shared taxpayer data via their use of the Meta Pixel and Google’s tools. Although the tax prep companies and Big Tech firms claimed that all shared data was anonymous, the FTC and experts have indicated that the data could easily be used to identify individuals, or to create a dossier on them that could be used for targeted advertising or other purposes.

This paragraph is woolly and does not appear to support the claim in the bullet point. But the full report has much strong wording on page 2: "Meta also confirmed that it used the data to target ads to taxpayers, including for companies other than the tax prep companies themselves, and to train Meta's own AI algorithms".

The logic of this claim, via page 19, appears to be: Meta says if their sensitive information filtering algorithm detected personal information, the information would not have been used for advertising, and they'd have sent a notification to the tax prep firms. They also confirmed the negative case: if no notification was received by the tax prep firm, then no filtering of their data took place. Meta was asked to provide copies of notifications they had sent to the tax prep firms and they did not do so. So the assumption is that none were sent, therefore no filtering took place, and the data were used as a signal in the advertising algorithm.

I don't find it to be an unequivocal confirmation, but the sources don't support your claim that this article is misleading or your claim that there's no reason to consider it a problem of the tech companies involved.

[1] https://www.warren.senate.gov/imo/media/doc/Attacks%20on%20T...

[2] https://www.warren.senate.gov/oversight/reports/in-new-repor...