The measure received 14 votes in favour, with the US the sole member to reject it. However, because the US is a permanent member of the council, it has the ability to veto any resolution brought forward
Unlike several previous resolutions regarding a ceasefire in Gaza, Wednesday’s measure was brought forward by all 10 elected members of the Security Council.
The US has vetoed four previous attempts at calling for a ceasefire in Gaza, on most occasions being the lone vote against the measures.
The UN has had nothing to do with contributing to the trend you have described. As unpleasant as it is, that is almost entirely a result of nuclear deterrence.