Why is there no edit or delete button on my calendar

To edit or delete an individual event in the calendar, you need to first select the individual event, and then you should see the Edit button in the upper right corner, and the Delete Event at the bottom of the page. The only difference would be if you have any Restrictions on in Settings.

The US Holiday calendar is a subscribed calendar, so it is not editable (subscribed calendars are not editable generally). Holi is the Hindu celebration of Spring, a good harvest, and fertility. The US Holiday calendar as of this year includes holidays for the 4 religions most commonly practiced in the US, Christianity, Judaism, Hinduism and Islam. (See: https://en.wikipedia.org/wiki/Holi).

You're welcome. Yes, that is from the US Holiday calendar, and you cannot edit or delete events on that calendar.