Can't tell if serious.

it's actually true

the word was coined during the Nuremberg trials to describe the murder the millions of Jews before the creation of the Israeli state. That is it's true definition and etymology

what aid group said that?

From the article:

Eight international aid groups, including Oxfam and Save the Children, said in a report that Israel had failed to meet the demands by the Tuesday deadline.

If you want the full list, though:

Signatories
Anera
CARE International
MedGlobal
Mercy Corps
Norwegian Refugee Council
Oxfam
Refugees International
Save the Children

Source: https://www.nrc.no/news/2024/november/joint-statement-israel-receives-failing-grade-on-u.s.-demands-in-gaza (this page has the full text of the joint statement and a link to the full report)

Hamas infested unrwa

UNRWA - the organisation that Australia, Canada, Finland, Germany, Iceland, Norway, Japan, Sweden and the European Union determined they should restore their funding to after investigations into allegations were concluded - were not one of the aid organisations referred to by the headline, no.