>>37577044She actually mentioned paying church taxes, but obviously didn't go into much detail, not just because muh no politics no religion, but mostly just because she's a dumdum who doesn't really understand all that complicated tax stuff anyway and just wanted to vent in general about how much she pays (now, that she makes good Holo money), and in that context, "church taxes" came up as an additional item on the shitlist.
It's also a little meme here on 4ch, some people occasionally shitpost with "[bad thing that happened to Kiara] haha, this wouldn't have happened if you had paid your church taxes lolol!" and so on, and with how containment breaking KFP are, the meme sometimes even appears in her chat, so she kept getting reminded of it.
As for what that ominous-sounding "church tax" actually is (for example, it says little to nothing about if you're actually religious or not), just read the wikipedia entry
https://en.wikipedia.org/wiki/Church_tax , the austria entry is a little bit thin but the german section (they have a very similar system) goes into more detail. And yeah, it's probably still a weird thing for americans especially who, despite being on average more religious than the average yuro, still find the idea of the state actually collecting taxes on your gross income for the church's behalf pretty foreign, but that's just the way things are done here and no one really cares (people mostly just leave the denominations silently and lol fuck that useless pedo club anyway)