Did the Scoobies have the right to judge Buffy for trying to hide the fact that Angel had returned from hell in Season 3? Not no, but HELL no. They had the right to be apprehensive, they had the right to demand that she explain her actions, and then pay her the common courtesy of allowing her to do precisely that. They didn't have to agree with one single syllable of her argument, but they should have been willing to at least listen.
But Jenny Calendar's death didn't give either Giles or Xander the right to set in judgement of either Buffy or Angel. The Scoobies were just as wrong in this case as they would be wrong in a quite similar case four years later, and I couldn't with any kind of consistency support Buffy's actions in Season 7 without doing exactly the same thing in Season 3, even if in doing so, I have to (shudder, gag, choke) defend Angel.
It wasn't as if Buffy was the one responsible for bringing Angel back to Sunnydale, and it wasn't as if she had been allowing him to go on any sort of killing spree since he had returned. For the former, Buffy didn't have the skill, and for the latter, Angel didn't have the strength. In truth, she was doing her job precisely. She had, upon discovering that Angel was back, taken him into custody and contained any sort of threat that he might represent by the simple expedient of staying with him during the night and keeping him in the mansion, restrained by sunlight, all day. "The Scoobies didn't know any of that, though," you might say. Precisely my point. They didn't have any valid information beyond the fact that Angel was back on which to base any sort of judgement. In other words, there was no actual case for them to judge in the first place.