is anonymity of tribler strong enough to make such things impossible?
No without censoring, just to provoke the ethical dilemma here
Good question. Our anonymity features are not mature yet and a single software bug can end everything. In practice, we believe Tribler is sufficient to provide basic protection from spying ISPs and governments.
The reddit post that you linked talked about a feature in Tribler where on startup, you would be asked whether you want to volunteer as exit node in our network. This was a non-intuitive design decision, which ultimately led to the situation as described in the post. Since then, we fixed that particular issue (you have to do more effort now to become and exit node), and we have taken additional measures to increase the security of our anonymous overlay.