there's 'get away with' and 'advocate in public' - for example a lot of the nobility will be involved in trade up to their eyeballs with hundreds of money making schemes - but how many will admit to it?
Bloodtheft is about as extreme an example as you can get of embedded hypocrisy. There aren't that many scions in Anuire, and almost all of them will be influential people of one sort or another, the person who openly admits that they see each scions as prey is immediately the enemy of all of them - even if the target might personally be quite happy to 'accidentally' usurp the attackers bloodline 'in self defence'. One should always remember the core of the noble understanding of justice 'if no one saw, or no one cares who it happened too, it didn't happen...'
You also get the god angle, which I had Loeren allude to - bloodlines are likely to have some religious import given their origin, are quite possibly the underlying basis for recognition of true nobility, etc, etc - if bloodline is a tradeable commodity then its deific value is undermined.
With goblins a lot comes down to whether goblins are just ugly people with green skin, elves are just skinny people with pointy ears and dwarves are short guys with excessive facial hair - or whether they are distinct species with different biochemistry, physiology, etc. I obviously lean strongly towards the latter and presume neurochemical differences underlying the observed social differences in line with, for example, different dog subspecies where different breeds have strong tendencies to different psychologies.
The bigotry side then gets involved - bigotry requires 1) appreciable difference between social groups b) interaction and c) competition to really take off. Here goblins lose out by being very distinct physically (and in my view socially), having a history of constant negative interaction, and competing for just about every resource. While there is plenty of reason for issues as a result, they is also scope for differentiation between the goblin types - the goblins of Medoere may for example be seen very different to their forest brethren and seen as a distinct species 'our valley greyuns ain't goblins you fool! You see paint on their face or an axe in their hand? Peaceful lot they are, lived in the valley for generations and never bothered a soul!' - bigotry can work many ways.