I'm neutral on this one.
Angel's first reaction is understandable. I'm not a parent myself, of course, so I couldn't possibly comprehend his grief but I can get a clear picture of it. He'd just lost his son, the person he loved more than he didn't know why it had happened or why his best friend had played such a vital part in it. Of course he's going to be angry.
That being said, Wesley's actions were also understandable. Now think about it this way: with Connor running around, what were the chances of Angel achieving perfect happiness? What about when Connor said his first word, or crawled for the first time? Would it be enough for him to momentarily forget all of the horrible things he done as Angelus? After hundreds of years of pure loneliness, this must have been incredible for him, so I think it would be, and I'd be very surprised if Wesley and the rest of the gang hadn't been worried about this themselves. Angel had been acting a little bit odd even before all this.
Then, a prophecy (which is basically a confirmation, in Wesleys mind) shows up and tells him that this will happen. He can't tell Cordy cause she's left, can't tell Fred or Gunn cause they'll insist that Angel is told...doubt there will be some rash decisions.
And, you can't forget that Welsey was going to ignore the prochey before the big earthquake. That was enough to scare him into thinking that Angel was going to hurt Connor and he was going to do it soon.
And Welsey knew that if Angel ever hurt Connor he'd never be able to forgive himself or Wesley for not telling him.
What I mean is, Wesley was going to give up his whole life just so he could protect Connor, and by extension, protect Angel.
So I think that when Wesley intentions were reveled, he should have been forgiven right away, maybe not by Angel but by the gang at least.
I can understand Angel, and maybe Cordelia but I thought it was awful the way Fred and Gunn just turned away from him.
But hey, without all this we'd never have Wesley/Lilah. 😀