So then is this a call?

Thanks for answers my first question regarding what is binding as a call. I have another question and this actually happened to me.

I'm in a home game, multi-table tournie, and I just joined the table. Blinds were at 50/100. I'm BB. UTG throws in 200. Everyone folds to me. I deceide I want to try and get him to fold. I announce that I'm raising to 1000. It's then that they point out that he's ALL IN. He had his arms in such a way that I thought he had chips left. Since he was all in he can't fold (obviously) so I retrack my raise and fold. They say that it's binding and that I have to call. I protest saying that he didn't announce he was all in. I had just joined the table and didn't know he was low stack. Does my argument have any weight? I didn't really have a big problem calling since it was only 100 more, but I stil had a weak hand.