It’s more of a basic observation from watching how things‘ve spiralled the same in multiple countries that have voluntary voting vs how that’s been avoided in places with compulsory voting It’s also the most common opinion in my country so at minimum it’s a cultural opinion rather than a personal one

When only a select few vote, it’s safe (and indeed effective) to completely ignore the wants/needs of the non- voters.
This leads to extremism- the easiest way to get more for your chosen few is to take more from the groups you don’t care about. This creates a feedback loop where you’re now incentivised to make it harder for those groups to vote (since you know they already dislike you) which means fewer of them vote and they become more ignorable and more ripe for you to squeeze in favor of your chosen. It also means you can focus for support from a group that represents a smaller and smaller percentage of the populace, because all that actually matters is what percentage of the voters they are.
Alienating the more moderate parts of your original base doesn’t matter - they’ll just drop off the rolls (or be cleared off by you) hell your vote percent might actually improve.

When the populace and the voters are always the same demographic this kind of thing can’t work.
It’s pretty straightforward math.

Extremism profits from making the demographics of voters heavily skewed from the demographics of the populace. Why would you allow that to happen when it’s simple to prevent with mandatory voting?

Well firstly it means voting has to be easy.
We’d never get voter id laws/similar designed to suppress certain segments of the populaces access to voting. The government can be sued by an individual/group that felt it was more difficult for them to vote, so they make damn sure that doesn’t happen. Poling places are plentiful. Even in the most remote parts of the desert they’ll send out vans to set up mobile polling places. If you’re working on Election Day your employer is required to give you an extra paid break just for voting. They send election commission staff into hospitals, etc.
everyone gets heard.

Consequently we get far far fewer of the fringe extremists in our politics than we see in the international news. Hard focussing on a radically obsessed fringe won’t get you into office (well, it might get a group 1 senate seat, but not HoRs seats).
Mobs chanting to hang the vice pres would never happen here - the kind of aggressive and divisive politics needed to start that nonsense doesn’t work when everyone has to vote.
the politicians have to play it safe.
Their base alone is not enough, they need to appeal to outsiders too.

It takes only a cursory glance at the American political landscape to see that the price of low voting percentage is very high indeed.

Oh plenty of our voters certainly aren’t living up to their moral obligations.
But the fact remains that mandatory voting has a hugely positive effect on government

Officially? It’s a fine. Not a big one - it’s like a hundred n fifty dollaridoos. Really the penalty for not voting is getting a worse society-a less structurally sound hospital in OPs tortured analogy

I think participants in society have an obligation to be Informed as well as an obligation to vote.

Of course I live somewhere where voting actually is a legal obligation and I’ve seen how much that’s improved our political discourse and participation compared to places with optional voting.

So from a utilitarian standpoint I just can’t see any way to support non compulsory voting.

We possess obligations to the others in our society being a somewhat informed voter is one of them.