Mathematically calculated centers for each and every subject on a multi-polar political world fall all over the place, are not consistent between one subject and other in a political sense and move a lot more over time as the miriad of opinion shift even if only slightly, so your mathematical "centrism" would pretty much be "one opinion today, another tomorrow and no political consistency".
Absolutelly, you can mathematically find a middle point for everything, it's just that averaging anything but the smallest count of political ideologies (two, maybe three) across all possible human and societal subjects is not going yield a small enough and stable enough area of opinions to add up to a political ideology.
Notice how every single one of your examples of a position is something framed as having only two sides, pro and anti.
There's a massive area of options in something like, for example, one's position towards the Muslim Religion, for example, neutral, pro-Sunni but anti-Xiite, pro-moderate Islam (for example, as practiced in the largest Muslim country of the World, Indonesia) but anti-extremist Islam and so on, and even these are massivelly simplified into pro and anti for ease of explanation (just the role of Hadiths in that religion and which should be accepted or not as "divine" guidance generates millions of options which are neither "pro-Muslim" nor "anti-Muslim").
I suspect you have heavilly interiorized at a subconscious level the "two sides" logical falacy to the point that even when you tried imagining multi-polar politics you still ended up with people on either "one side" or "the other side"on a per-subject basis, which is just moving the two sides logical falacy from the general to the detail (an improvement, yet still anchored on the same reductionist framing and thinking about options in politics and society)
You suspect wrongly because you are reading too much in a simple example that was meant to look like someone being in favor of both left/right talking points