Loyalty to Others is a Vice

Loyalty to yourself is a virtue, particularly loyalty to your own given word.

However, consider loyalty to someone who betrays you.

1. If loyalty is maintaining faith with the traitor, it's supporting a vice.

2. If loyalty allows you to break faith with a traitor, it's merely contracts. Loyalty in this case is isomorphic to selfishness - if the deal is no longer profitable, you break it. 

And that spans the entire space. Either you can break loyalty or you can't. If you can't, it's a vice. If you can, it's a distinction of no distinction, which is a lie, which is a vice. Loyalty to someone who hasn't betrayed you is nothing more than continuing to collect benefits.

In use, loyalty is expounded by traitors who wish for you to maintain your side of the broken contract. Loyalty (to others) is pure viciousness. 

P.S. I hope I don't have to explain that being a slave to your impulse id is not a virtue.