He would not have been slaughtered for letting the race end behind the safety car at all, people would have been disappointed if that was how it ended, but people would have understood the reasoning behind the official sticking to the rules over simply making shit up as he went along which was what happened with that selective unlapping nonsense.
There's no probably about it, his decision was objectively a clear error that influenced the result of the race in favour of one driver over another, his position became untenable once he did that and the only real surprise is that it has taken this long for him to go.