That's the result of a ten day long battle when two of the strongest logia users, who also happened to be among the best fruit users, going at it without holding back. That ain't just a side effect.
Depending one the fruits, logia spam can destroy an island, similar to what happened to Banaro Island, but that ain't creating a climate change and splitting an island right into 50/50 with it. Attacks/moves might at best change the weather for some time similar to BM's homies, if the attacks were to be directed at the clouds, but even that is a stretch.
Instead we have 2 canon examples of an out of combat effect doing basically that tho: Ace's snow stop aura and GB's walk by forest spawn.
So I'm going to assume that this is what caused the situation on PH aswell, just to an extreme extent, because of the longer timeframe, with climate changing effects that are super annoying and borderline dangerous, cause of the nature of these fruits. While neither effect could gain the upperhand over the other (cold ~ heat), hence the 50/50 split.
What it boils down to: In my opinion your comparison is off. You are comparing Law's and WB's peak moves to what seems to be the aftermath of just one part of logia awakening.
Besides that terrain/climate changing quirk logias will also have their very own peak attacks aswell and I'm pretty sure that those will be incredibly powerful, if Ace's Entei is anything to go by.
Thus the whole package then leads to S-class logias > A-class logias ~ S-class paramecias and so on. But we ofc can agree to disagree
