I can understand that metadata is valuable -- of course it is. You can learn a lot from metadata. But more valuable than the actual content? Give me a break.
Something can be bad without being literally the worst thing ever. Pointless exaggeration like this does nothing for the cause of privacy.
Getting high precision is difficult when done on "all content", especially considering the multitude of languages and dialects in Europe. At a certain point, more data does not result in better output, sometimes it's actually detrimental
The patterns that arise from metadata are much more generalisable and there's less of it, so it's easier to search through
Widespread enough, this can be used to find dissidents today, suppressing ethically legitimate uprisings against injustice.
[1] https://blog.wolfram.com/2017/06/29/analyzing-social-network...