So it may not fall into the unsolicited mail clause.
This is of course independent on the fact that this is a despicable practice.
I mildly participated in the preparations for GDPR in my (large) company and the sharing of third party personal data was one of the points. It was a few years back so my memory may be at fault here.
The point I am trying to make is that the person who is sharing the information takes the responsibility, not the application (which uses it as advertized, at least according to the quotes here as I did not read the tos myself).
Imagine you have a friend in debt and start receiving such notices ? They’re collecting private information on you (your name, your phone number or your email) without your consent.
IANAL but I’m pretty confident it falls under GDPR.
(Sans parler du fait que les mecs qui font ça sont quand même une belle bande d’enfoirés)
If they do not, they are to blame because they willingly shared the contacts. The app used them per their tos.
(et oui, je suis d'accord que c'est un vrai dick move, aparamment c'est une pratique courante en Inde pour ce genre d'apps)