The key problem with bothsidesism ain't that the truth ain't always in the middle, even though the truth ain't always (or even usually) in the middle. The key problem is that most questions don't fall along a single spectrum, let alone a single binary dimension. What I mean is that enigmatic, everyday, life-is-complicated-isn't-it thorns are usually far more complicated than "A or B" or even "somewhere on the trail connecting A and B." Just for a handy example, let's say A = "the world is spherical" and B = "the world is flat." The universe strongly resembles A rather than B, but when many people strongly believe B, there's usually something compelling about B other than, simply, "it's so wonderful to be wrong, isn't it?"
In this case, when you step outside and go for a walk, the ground is mostly flat. You could walk your whole life and keep the impression that, overall, the ground is flat, with some bumps and dips. People believed the world was flat because it was a compelling - and partly true - description. It was workable. People believed the sun went around the earth for much the same reason. Neither description is stupid or entirely inaccurate. They are good descriptions within a certain frame of reference.
Now, curiously, whether "the earth is flat" is a good, workable description doesn't have too much bearing on whether "the earth is spherical" is a good, workable description. Both have descriptive power up to some level of realism. "The earth is rock," likewise, has descriptive power up to some level of realism. That last has, of course, even less to do with whether "the earth is spherical" or "the earth is flat" mirrors reality, but we know from daily experience and education that all three can be decent approximations in practice. Earth is a "rocky planet" when compared to Jupiter (yet we ourselves are not rock, and neither are the oceans or the ozone layer). We park the car on level ground when the parking brake doesn't work. We look at a globe for sharper insight about the sizes of regions. Yet the earth is not entirely spherical, so that description is also false if we need to get binary at high resolution.
When A is "truer" than B, a scenario we regularly face, and still there is disagreement, it really helps tremendously to understand what's GOOD about B, and, additionally but perhaps quite differently, what's appealing about it to its proponents. I have no trouble seeing why people believed the sun orbited the earth. Whatsoever... None! It's the most understandable - and relatable - broadly erroneous belief in the world. And if all we can do is fault the belief and spite the believers, we are poor communicators indeed, and maybe sometimes not very good people.