I disagree. I don't think an hour - presumably the OP would have to get home, also, so would have had to leave before 8 - is enough time to politely socialize with someone offering you hospitality without implying 'It's all about the food!'
I do agree that Annie agreed to it, though. Perhaps her delaying tactics signify that she wasn't happy about it. Obviously not the best way to go about it.
Of course in this case the OP didn't get to eat so it's a moot point, but in general, this line of thinking puzzles me.
It was a simple dinner (no multiple courses or anything), we could have eaten and been done in 30 minutes. With two toddlers, short meals are ideal.
And as I was okay keeping DS out a tad bit late, we could have socialized for another hour after dinner, until eight o'clock. We only live 15 minutes away, and that would still get him in bed before 8:30.
Regarding my husband, I don't agree that he should have had to miss out on his time with his friend. It was already determined that Son and I would leave early--and in fact, we left at about the same time we would have, if dinner had been ready at 6:30. As for his idea of rudeness, I fully understand it because I was raised with the same people-pleasing mindset he was. It's not correct, mind you, but I understand why he thinks that way and it doesn't bother me.
Snooks, DH explained why we were leaving. By that time, I felt uncomfortable enough that I didn't want another uncomfortable interaction with them.