The EO tend to point to Dioscorus as a heretic, adhering to a monophysite Christology simply because Dioscorus was trying to rehabilitate Eutyches who was in error. The fact is that even at the council Dioscorus was not condemned for heresy, there is no evidence for this whatsoever. This idea comes from later interpretation of Dioscorous' actions and not any decision by the council of Chalcedon. Dioscorus later did condemn Eutyches who persisted in his error of a monophysite Christology, which apparently is overlooked. But what about the Oriental Orthodox perspective which is almost entirely ignored by the Eastern Orthodox?
From our perspective we were very suspicious of Leo. Why? Well, like Dioscorus making the Eastern suspicious by supporting, and attempting to rehabilitate Eutyches, Leo supported Theodoret, a known Nestorian heretic. When Dioscoros read Leo's Tome he most likely thought it was suspicious in its wording, which is probably why he refused to read it. Not only that, Nestorious himself said that Leos Tome was a "vindication of the truth." So we had enough reason to be suspicious of Leo and his intentions to reject what was taking place at Chalcedon and the Antiochene formula. Of course in hindsight we know that Leo was not a heretic and that while he was friends with Theodoret he was attempting, like Dioscorus, to rehabilitate Theodoret, even rebuking his Nestorian Christology in letters to him.
You will find most, if not all, Oriental Orthodox accept both EO and OO formulas, namely because St Cyril himself affirmed that both formulas are Orthodox, even though he preferred the OO formula to the EO formula. The formula itself is pretty much a non-issue yet I find so many EO are obsessively focused on this, again telling us what it is we believe and then attacking it. Without ever actually asking what we believe, or if we even accept both formulas. We are not monophysite, never have been and never will be. We have adhered to St Cyrils formula of "One nature united out of two" which was accepted at the 3rd council. How exactly could that be Orthodox in one council and then heretical in the following council?
At any rate, we accept both formulas.