Fact is that Jolla Ltd. does not guarantee that they won't sell private data - they can't guarantee it. If Jolla Ltd. is bought by another company than this data won't be deleted but sold together with all other assets. And that a prospering small company is bought by a big one is nothing uncommon. Nobody could ever have imagined that Notch would sell Mojang to- or that Nokia would be bought by MS. So this is not "nothing more than speculation, without any good reasons, even."