The idea that anyone should be "explaining observations" rather than drawing conclusions from them is at the core of the disagreement here. We're not trying to "explain sunsets", despite the repeated cries of those who claim to support science, but whose actions betray them. We observe, hypothesise, verify, and conclude.
That seems at odds with the wiki, which frequently uses the word 'explain' in exactly that manner, for example:
Horizon limits are easily explained by the fact that air is not transparent and refraction diverts/scatters the rays over a large dense medium, so it is not possible to see past a certain distance.
Aside from being obviously wrong (why can I see the top half of a distant ship, or mountain, but not the bottom, if the cause is the limited visibility?), that is clearly an attempt to
explain something, in precisely the fashion that you are claiming that you do not do. Moreover, where is the verification of this? What we observe directly contradicts this hypothesis.
I would suggest that a more fundamental question for FET is not so much why there are sunsets, or why things disappear from the bottom up as they get more distant, but why there is a horizon in the first place. If the earth was flat, then we wouldn't expect a distinct, crisp horizon at a relatively short distance from the observer. The wiki is muddled on this - in one place, we have this:
Light from objects too far away either hits the ground or is bent upwards before it reaches us. This also explains the "sinking ship" effect: the bottom portion of the ship appears to sink into the ocean because all of the light either hits the ocean or is bent upwards, but light from the top portion will be able to go further down before being bent upwards and becoming visible to us, since the ocean is lower relative to it.
But then elsewhere we have this:
It is believed that the bending of light does not simulate the rate of globe earth curvature. Instead, the bending occurs more gradually over a greater distance.
But if the bendy light doesn't bend enough to 'simulate' (?) the rate of globe earth curvature, why would there be a distinct horizon behind which things appear to disappear?