As long as data is not de-aggregated and de-anonymized there is no issue here.
I see no relationship with the GPDR as this law applies to personal data and the agreement explicitly stated that data must be aggregated.
As long as it is used to know people flow or for statistical purposes, I see no wrong here.
The other political statements and comparisons he makes, well are unrelated and sincerely looks like political propaganda to me.
I currently work for an spanish ISP, and I can tell you that this test will put a lot of stress in the ISPs network. Querying, for example, cellid for so many phones simultianeously is going to be a problem. Other data like IMSI and so on is not a problem because it's stored in a database.
For people who is scared of this, ditch your phones because extracting your location, subscriber id and other info is, honestly, trivial. It is not to do at scale, but if someone wanted to spy on you and had access to the ISP network, be it via hacking into it (very difficult in the one I work for, but may be possible), or using a law, they can know where are you with very little effort.
Awfully hopeful there.
"The other political statements and comparisons he makes, well are unrelated and sincerely looks like political propaganda to me."
I would say the same about your assertions of innocence and presumption that the data can not be de-anonymized. If the "propaganda" is supporting user privacy I'd say you're on the wrong side of this discussion.