No, the US was not supposed to participate in the 'human rights council' hearinghuman rights council.'
As you can see from the statement above, that report was not quite correct. The US, as a matter of principle, boycotts Item 7 on every 'human rights council' meeting agenda, because that is the permanent items for excoriating Israel. If you can't read the image above, you can find the statement here.
The Europeans, on the other hand, according to my sources, violated an agreement with Israel by commenting on Item 7. The Europeans have a deal with Israel that if Israel submits to the Universal Periodic Review, the Europeans will boycott Item 7.
Of course, a much more principled stance for both the US and Europe would be to leave the 'human rights council' altogether. But that will have to await new elections in the US.