One word: Brexit
It should not be a surprise that social services are taken advantage by a large population of rural/republican voters who vote in candidates who’s explicit platform is removing or diminishing the very social services they depend on.
If they're a single-issue voter then - by definition - they are not voting against their interests. They just have different interests than you.
Maybe you care about a million things, mostly revolving around taxes.
Maybe all they care about is whether or not someone else can get an abortion.
That's THEIR interest.
It's in everyone's interest to get a good deal for their money. For example, we should all be for an efficient government, and efficient markets. However folks vote against those all the time without thinking about it, because their focus is elsewhere.
If you don't care about money, and only care about telling other people what to do - money isn't your interest. Telling other people what they can and can't do is your interest.
You seem to be incapable of grasping that other people care about other things than money.
The single issue of that voter maybe be the most overriding important issue for them, but it doesn’t mean that the consequences aren’t still a net negative for them (Or especially society as a whole).
To my previous point, they may be doing so with full knowledge or with partial knowledge. They may knows Candidate X supports Issue Y and that is their top line issue. They may not know Candidate X’s position on Issue A, B, or C.
Those positions may have an impact on what they would actually prefer to vote on.
Candidates are not single issue, even if voters are, but they often advertise them that way to limit single issue voters from knowing or caring about anything else they represent.
You can also vote for someone who says the thing you like or prefer but the reality of their plan is contradictory to the stated goal. (Preventing Medicare from negotiating drug costs will somehow make them less expensive, according to some candidates)
To be clear my point isn't to blame voters specifically. My point is that due to imperfect knowledge (Anywhere from willful ignorance to not learning enough about a candidate to the particular candidate straight up lying about things) people make choices in voting that can and do contradict their own interests.
We live in a democracy.
The idea that we vote to screw ourselves over completely is strange.
Some people forget that everything isn't a zero sum game. Something can be good for companies and not bad for you. And something can be good for you and not bad for companies.