I'm not sure it is true that "discrimination = bad" is a "liberal frame".
On the opposite, I feel that this idea is quite common amongst non-liberals who misinterpret liberals. A liberal would say "this is discrimination, this is bad", and the non-liberal would hear "this is discrimination, all discrimination is bad, this is bad". But similarly, one could say "this is sharing private information, this is bad". Does it mean that the conclusion is that sharing private information is always bad? Even when you share info with your family? Or when you open up to your partner? The mistake done by the liberals is that they assume the context is obvious. They assume that it is obvious for everyone that "that particular discrimination" is one of the bad ones.
(and, sure, I'm sure some liberal people also don't get the distinction and fall into the mistake of thinking that all discrimination is bad. My point is that it is not particularly a "liberal frame")
There is a good way to estimate if a discrimination is "the normal one" and "the bad one". A discrimination is bad if the real principal objective is to favour the in-group and disfavour the out-group.
People use that criteria themselves unconsciously. If I say "I'm not giving this to Steve because I know they don't like it", people will just think it's fine. If I say "I'm not giving this to Steve despite the fact he deserves it but I don't like him", people will notice it's unfair. I think liberal people just assume this is obvious, or even not realise it themselves.
This criteria works well. For example, in the examples you gave, none of these actions have been done because "we don't think the people we excluded from the advantage don't deserve it for not being our in-group".
But it is also true that when it comes to conservatism, there are elements where the discrimination is made to exclude the out-group not on fair principal reason, but for the principal reason that it is advantageous for the in-group and the out-group is arbitrarily considered "not worthy of it".
>A discrimination is bad if the real principal objective is to favour the in-group and disfavour the out-group
Come on, the outgroup is indefinitely big and the resources are limited. You buy icecream for your kid and not for the random kid. You favour the wellbeing of human race to that of aliens. Presumably you understand the will of Sentilese people to not share the island with strangers. Does it matter whether they think "we have to do this to protect our existence" or "we fucking hate white people"?
I think if you try to define what forms of favouring the ingroup are justified and what it means for Steve to deserve X you'll end up with something like "discrimination is bad when it violates the liberal moral intuition". Don't get me wrong, I love meritocracy and the world it built, but I don't think we can navigate millenia worth of social constructs with a simple rule of thumb.
I would say generally speaking under Liberalism the notions of different registers or rings of “collective” are illegible. There is only the individual and the collective, not different types of collective with different rules and protocols.
This is why even ideas like the nuclear family are hard to define or defend within Liberalism.
Remember that Black Lives Matter had on their website a declaration that they rejected the notion of the nuclear family.
Along the same exact lines the notion of what makes someone a citizen of a Western country is very hard to define or discuss. In some sense every person on earth is basically an American, they just haven’t been officially granted citizenship yet. No one can actually define what particular qualities qualify someone to become an American citizen or not, everyone just has vague notions and some ad hoc mishmash of various financial or political interests.
This makes discussions around illegal or legal migration in the West very difficult to have, purely on an intellectual level in terms of the categories.