You're right, your inference method isn't science. Science is "given two relatively similar municipalities, if one enforces a mask mandate, cases decrease in that municipality compared to the other". A finding that was repeatedly verified on the scale of cities, counties, and nations.
That months after mask mandates were enforced, case rates went up everywhere, including in places where masks weren't enforced, doesn't sound like it has particularly much to do with masks.
What isn't science, is every internet genius that can divide one number by another, or compare two numbers but ignore everything about the context, is suddenly a self-proclaimed expert.
Here's a notion. Listen to real experts, and do what they advise. Instead of spinning yourself up and posting nonsense.
That months after mask mandates were enforced, case rates went up everywhere, including in places where masks weren't enforced, doesn't sound like it has particularly much to do with masks.