Not sure which side of this I come down on tbh, it's a pretty clear and obviously crippling dupe bug when Tinkers and GT are both installed. The ability to easily and infinitely dupe metals such as iridium? .. that can't go unaddressed.
Greg's message is a dick move, buuuut .. we don't know what's gone before. Greg references mDiyo "telling everyone that it's his fault", so is his message a defense/counter rather than an attack? .. there's enough anti-GT sentiment in forums such as this that a lot of people seem ready to instantly side with mDiyo because they dislike Gregtech, but is that a reasonable response given the situation?
Tinkers is new to the pack and frankly, I love it. Love the concept, love the design, buuuut .. devils advocate time. It's being incorporated into a pack where 2/3 of the major sub-packs use GT into which it introduces a massive exploit. Regardless of whose coding style you prefer, it's a dupe bug/feature that can dupe any block that has a furnace recipe and (even if you dismiss the vast majority of affected blocks as unimportant) it's still a dupe bug/feature that is introduced by mDiyo.
In the end, it doesn't really matter whose "fault" it is. I've no doubt that the ability to dupe metals will get patched shortly, but if mDiyo's attitude is "it only affects gregtech so it's his problem" then it hardly speaks well of him.
We already have one GregoriusT; can the pack support another prima donna mod author?