This monetization scheme benefits the botnet controller and the developer who added the SDK and not the user who likely did not realize they signed up to become an exit node.
The existence of an app brings users value, else they wouldn't use it.
and I doubt these apps are really Free versions - do they support user modifications and access to the code? If they did support the four freedoms maybe the fsf would have something positive to say to balance it out?
Popa is an illegitimate and botnet[1] that no end user knowingly/willingly uses.
1: https://krebsonsecurity.com/2026/07/fbi-seizes-netnut-proxy-...