You are completely uninformed.
Not only was there a large contingent of Orthodox involved, the bulk of the Latins were Venetians, not Normans - the non-Venetians were mostly Lombards and Flemings, with some Alsatians.
There were probably some Normans present - but "almost entirely Normans"? Please.
The dynastic dispute part was a polite fiction, so that the Crusaders could sack Durazzo to pay for their passage to Constantinople.
I see. So Alexios III conspiring against his uncle, the Emperor Andronikos and being forced into exile to live among his Muslim patrons never happened. His younger brother Isaac was never made emperor either, I guess. And he never deposed his younger brother after he returned from exile, nor did he hold his brother prisoner and put out his eyes. And Isaac's son was not really angry about his father being overthrown, imprisoned and mutilated.
That was all made up by Baldwin and Boniface - everyone in the Byzantine ruling family were getting along just fine, and everyone in the family was really happy that Alexios was sitting on the imperial throne.
In reality, there was a bitter dynastic dispute, and in reality Baldwin and Boniface didn't sack Durazzo.
Perhaps you are confused: Durazzo was actually sacked by Robert Guiscard - who was a Norman leading Normans, unlike Baldwin and Boniface and their troops - in 1081 in a battle with Alexios I or 123 years before the sack of Constantinople.
The Pope belately expressed his regret, but nobody believes that Rome wasn't thrilled to have the Greek Church "brought to heel".
Even if one were unkind enough to believe that the Pope viewed these matters solely from a geopolitical standpoint and not from a spiritual one, your analysis would still be completely wrong.
In the old rivalry between the Normans of Sicily and the Venetians, Innocent II was firmly on the side of the Sicilians who supported his agenda for defending the Papal patrimony against the encroachments of the northern Italian powers of Lombardy and Venice. Boniface - a Lombard prince - and the Doge of Venice were the Pope's political enemies. Their success threw a wrench into his geopolitical strategy.
Additionally, Innocent III was a vocal supporter of Otto's claim to the throne of the Holy Roman Empire against the claims of Philip of Swabia.
Boniface was Philip's cousin and main supporter in Italy.
Boniface's success in Constantinople helped bring about Philip's eventual crowning as Emperor, one of the most bitter moments of Innocent III's pontificate.