I get your frustration at people saying it's Elrond's fault, but maybe, if you know the issue is bad code, could teach us devs a bit on what is the bad practice they used and when and how to avoid that?

I totally agree with this. If they are 100% aware of this kind of "trick" (let's call this like that if Elrond don't want to call it hack), why don't they share knowledge ? I mean, is it so well known that you can revert a transaction ? I personaly never blamed Elrond for this, I just think the hacker is taking advantage of blockchain complexity. But this not the answer I was waiting for " Not our fault, your code is shitty. Good bye".