[fdiskl]

Read the GDPR or national equivalents in the EU and that will show the legal argument - literally that there are a group of laws defining that this isn't allowed in those jurisdictions. Whether or not you're convinced or not is of no consequence to the laws.

[kevindong]

Can you point to a particular clause or section that indicates this wouldn't be a compelling usage (e.g. performance management of employees) of personal data?

You along with all of the other commenters have just responded with the generic assertion of "European privacy rights aka GDPR, duh." But then you don't actually support your assertion whatsoever.

GDPR is not a blanket prohibition on collecting data.