Apparently it's controversial that citizens/Permanent Residents should get benefits foreigners do not, or even to say so (I got blocked by someone I had never interacted with after raising that question, so I assume that was the reason).
One claim is that foreigners pay as much taxes as Citizens/Permanent Residents, so they should get the same benefits as them.
Yet, this misconstrues the nature of the relationship of a state with its citizens.
Some Singaporeans will bring up the usual canard of National Service to justify Singaporeans/Permanent Residents getting more benefits, yet one does not need to appeal to particularities of Singapore, since we can see that even in liberal, developed countries, citizens and permanent residents receive more benefits from foreigners.
I can think of at least 4 justifications for giving citizens and permanent residents more benefits than foreigners:
1) Permanence
2) Duration of past relationship
3) Kinship
4) Reciprocity in civic duty
1) Permanence
Foreigners are not assumed to be staying in the country permanently or even for the medium/long term, but citizens and permanent residents are.
This is also why in developed countries permanent residents get almost the same status as citizens - for example, generally being allowed to reside there permanently.
In most countries, foreigners who have been in the country for a while are allowed to apply for permanent residence, to signal that they want to enter into a more permanent relationship with the country. So foreigners are not discriminated against per se. This application may be conditional upon having/having have had a job, though, so permanence isn't the only justification (and we can also see this by how a country still has a relationship with citizens who are residing abroad permanently).
2) Duration of past relationship
Whereas the first point is about the future relationship between individuals and countries, this is about the historic one.
A foreigner typically has not been in, or had a relationship with, his host country for very long (if at all, for a new foreigner).
Yet citizens have had one (typically since birth) and permanent residents usually have had one for a period in the past too.
It is reasonable to have a closer relationship with someone with whom you have history than someone with whom you have little or none.
3) Kinship
One can think of the relationship a citizen has with his country as similar to that between that of a parent and an adult child.
Nations are imagined communities, after all. So besides the relationship one putatively has with one's other citizens, one also has a relationship with the state.
So just as we would not fault a parent for helping his adult child with a downpayment on his house but not a colleague, we wouldn't fault a country for treating citizens better than foreigners (even if the parent interacts a lot more with the colleague and indeed if his job depends on the colleague but not the child).
To a lesser extent, this applies to permanent residents (perhaps one could see it as a relationship between a parent and a child-in-law.
4) Reciprocity in civic duty
Interestingly, we can see that in jurisdictions with jury duty, if you are eligible to vote, you are eligible for jury duty too (this is not just limited to citizens - in the UK, Commonwealth citizens who can vote must do jury duty too).
Voting, too, is considered a duty (even if there might be no penalties if you don't do so).
So privileges also come with responsibilities - and these are not purely monetary.
From these 4 points, we can see that there is a reciprocal, enduring, historic relationship between a country and its citizens and permanent residents that goes beyond the payment of taxes and the bestowment of benefits.
Addendum: Naturally, citizens should also receive more benefits than permanent residents due to the reasons above.
Related posts:
How votes for all (including non-citizens) devalues the vote
Why giving the young more votes has implications you will not like