There is an assumption that holding a long time horizon results in a better future for the actor. That by factoring in their future state rather than always preferencing their current state, leads to a better now for them in the future.

Many of these high time preference options are facilitated by the fiat system which is essentially stealing from it's participants. By choosing a low time preference option, you are often choosing not to steal from other participants.

The link between time preference & ethics has a lot to do with choosing not to participate in a corrupt system. There is nothing ethical or unethical about choosing to make a fishing rod over catching a fish with your bare hands. It's more ethical to buy a car with money you have saved than to borrow from a lender who creates the currency with an entry in their system.