He meant that this was the time to kill Penelope's suitors.
Explanation:
When Odysseus says "The hour has come to cook their lordships' mutton-supper by daylight. Other amusements later, with song and harping that adorn a feast" he means that the time has come to kill all Penelope's suitors, which for her it is as pleasurable as a banquet and that will be celebrated later with songs and harps, because the suitors is a problem that has been ended and that will no longer affect his family.