Well, I see that posters either loved this film, or hated it.
It is more than obvious that those who hated it did so for political reasons. Pick any reason. The uniforms are not accurate. The history is all wrong (yeah, everybody is a history professor). It's racist (but you expected that would pop up, didn't you). It's only for Catholics (well, finally something for Catholics). The acting is bad (I've seen worse).
Someone complained that F. Murray Abraham spends the whole film screaming. Er, no. Only in two scenes. In one he was addressing an entire army. And in another he was trying to make himself heard over the thunder of battle. May I politely remind our distinguished critic that there were no microphones in those days?
It also looks like that the mention of the date of the event - Sept 11 - went down some tender throats like battery acid. Yeah, those historical coincidences are a (bleep). Haters of this film also wasted no time pointing out that critics panned the film (and we know that critics are infallible). Well, consider it from their perspective. These exalted critics must have remembered what happens when a certain religion is mentioned in an unfavorable light (Charlie Hebdo, anyone?). So maybe the critics panned the film more out of prudence than displeasure.
Is the film perfect? No. Is is 100% accurate? I NEVER saw a 'historical' film that got the historical facts 100% right. And I've been around a good bit. But I enjoyed Day of the Siege.
IAC, watch the film and make your own decision. A quaint concept, I know. But some of us still believe stick to it.