Hello,
on Linux upon first launch it set some wrong non existing Desktop/Download folder as default for me, so i have used real Download folder nearly all Linux use /home/userhere/Downloads
But failed to discover that the app will begin sharing its contents. It is very wrong idea to share it by default as it is set now, because to Downloads folder you also download sensitive documents and so on.

So i propose you disable by default the Settings option "Added library folders shared by default" or somehow clearly warn upon initial setup that the Download location content will be shared and it may be the risk.

You seems to also follow symbolic links which makes sharing more risky too.