That's not even one of Uglúk's faults

[littlemanpoet]

Here's just the first instance I found.

'So you've come back?' [Uglúk] said. 'Thought better of it, eh?'

'I've returned to see that Orders are carried out and the prisoners safe,' answered Grishnákh.

'Indeed!' said Uglúk. 'Waste of effort. I'll see that orders are carried out in my command. And what else did you come back for? You went in a hurry. Did you leave anything behind?'

'I left a fool,' snarled Grishnákh. 'But there were some stout fellows with him that are too good to lose. I knew you'd lead them into a mess. I've come to help them.'

Grishnákh twice makes sarcastic remarks regarding his motives: to see that prisoners are safe and to help stout fellows. Uglúk remarks upon better thought, which (1) denotes thought process and (2) value. These are statements of value, not in terms of money, but ability and character, which denotes moral standards.

Following this is Uglúk's taunt about the Nazgúl and then Grishnákh's retort, which serves to reveal that Grishnákh is more evil and more knowledgeable than Uglúk. Then Uglúk says,

'You seem to know a lot ... More than is good for you, I guess.'

"Good for you". This again denotes moral sense.

And both exchanges show that each orc is pointing out blame in the other and virtue (of a sort) in himself.

There are other instances of this kind of exchange, both here between Uglúk and Grishnákh, as well as between Gorbag and Shagrat in the Tower of Cirith Ungol.