The final summary of the second article says it all, in my opinion:
Since Mullvad VPN by law is not required to collect any data related to our users’ activities online – and since the pure purpose of our service is to protect users from collection of such data – it is in our interest, our customers interest, all our employees and owners’ interest to not collect any data and therefore there is no reasonable grounds to doubt that we do not collect any data about our users’ activities online.