Yeh that definitely sucks they've rigged it up in a way that's unusual for this type of work and also forces you in to this situation. Redirecting is good and probably your best option, canny and sensitive people will notice you doing this and take it for the hint that it is but dense or uncaring people will probably carry on steering things in to places you don't want to go. If you're forced to eat with them then yes redirecting the conversation will work up to a point but it is a subtle skill to do so non-obviously. It's hard to advise specifically what to say like a script, though I would say if you just totally ignore the question altogether and switch topic very bluntly it's going to come across strange and prompt confusion and questioning. You'll need to somehow maintain the initial thread of their topic as lip service and then turn off down an unrelated avenue fairly smoothly. It's what politicians do professionally. Reading the other responses to your post I think they've got some really good ideas on how to deal with this if you really get forced in to conversing against your will. It's a subtle art of contributing basically nothing and rephrasing their same question back to them. I think another commenter suggested something along the lines of "I don't know much about that what about you?" and similarly bland and useless resonses. This is friendly enough not to piss anyone off and lame enough to be totally uninteresting which hopefully invites little follow up. If they continue on their original track, you can combine this with seguing to another topic.
I didn't suggest this to you initially because it doesn't sound like your natural style and I think advice is best if it allows the recipient to handle things mostly in their own way while helping to avoid pitfalls in doing so. I guess you'll have to navigate this daily frustration in a way a little outside of your comfort zone by carefully appearing to engage whilst really not and hopefully they'll find you so boring they don't bother anymore. Hopefully you don't mind this giving the impression that you're a boring person to the remaining 50% of your peers that don't bother you so much but sometimes it's a necessary evil.
Is that including the r/Australia main sub? I didn't go there very often because, well, it's just going to parochial at best but it was somewhere I'd see the occasional top post now and then. I probably first ever visited it and spent any time there around 2013 and it was weird man. It was so hardcore right-wing and overly political that it was impossible to browse it functionally, if I actually waded in on anything explicitly political in nature it was a nightmare. I also even had weirdly innocuous stuff I said just straight up deleted by mods, I'd never up until that point had interaction with any reddit mods so that felt just crazy. That was an abiding and striking memory of the place that I found very odd indeed and weirdly out of step with the experience of reddit in general. One gets used to their bubble and Reddit had always felt like 20-30 something year old male liberal-ish tech enthusiasts so when you accidentally step in to a mixture of a Liberal voter retirees and the One Nation fan club it's disconcerting. It meant that I was even less likely to ever really see or actively seek anything from that corner of Reddit.
A few years later I returned there, I can't remember when this would have been but I guess maybe 2018-ish? And then it'd gone a lot more normal. It's a general forum and there for interaction so I try not to describe and analyse exclusively through the lenses of 2 dimensional political leanings but it's useful here and I think it was accurate to say, it'd settled on a mainstreamish slightly left of centre type of crowd for most posts where politics featured. This was noted by the occasional disgruntled conservative who disliked having to be in relative minority, but nowhere near the vitriole of before. I always wondered if there'd been a cleaning of house or something, and how that managed to happen if so. I also always wondered where the previous majority of One Nation admirers had scurried off to. Having also quit Reddit a year ago, obviously I've not been back and between 2018 and last year I wouldn't have been in r/australia a great deal anyway, but if it's gone full Murdoch as your describing I wonder what weird forces were at work to bring it back to its former repellant mix of visitors and moderation policies.