The UK is not in the Schengen travel zone and had no right to be accessing the data or sharing it with other foreign powers.
The problem is that too much power is collected in one place that encourages bad actors to weaken security so that they can later do a grab and dash with "Plausible deniability".
When people raise this warning it is dismissed as fear mongering, when the fears turn out to be justified people side step the issue and argue that the title should be millions instead of all.
Some people have argued that the EU do not have a database of EU citizens fingerprints, but they have been building that database since 2004 [2].
These massive databases of personal information represent too much of a risk and should not exist. The only way to protect power from corruption is to distribute the power rather than consolidate it.
[1] https://euobserver.com/justice/145530 [2] https://uk.reuters.com/article/uk-eu-fingerprints/fingerprin...