There is no reference for that!

It is assumed we are smart enough to realise that if the weather is above Alternate Criteria, whether it be for the full period or inter/tempo, we don't need any extra fuel. It is not necessary for the AIP to state that.

The AIP section that deals with Alternate Aerodromes, Weather Conditions and INTER/TEMPO is:

ENR 1.1 - 92, start at para 8.8

People generally want to get to their planned destination. Most people would probably rather be bumped off a flight, sit at the bar for an hour, and take the next flight to their planned destination rather than ending up at an alternate.

If you have a forecast requiring 60 minutes holding and you instead elect to carry minimum alternate fuel then what do you do if you get there and have to hold? You can't, you don't have the required holding fuel, so you have to go to the alternate. Who wants that?

If you're thinking that you can take alternate fuel but then use it to hold, well you're basically carrying less than the minimum required fuel for the flight aren't you?

It is a question of economy. Consider holding for an hour burning say 3000kg while holding and another 120kg carrying this extra on a short sector versus expenses airline will incur diverting to alternate.
Leaving some bags behind to be delivered by a next flight seems like a reasonable idea in this context.

Comrade