How do I remove "align to baseline grid" as the default?

Barb is right on the money here, but I'd want to add that you should also double-check the Basic Text Farme in the Object Styles (Window -> Styles -> Object Styles -> Text Frame Baseline Options) to make sure that it's not turned on there, as well. 

Hi @JasonKillinger:

Here is a post that describes how to set and remove defaults in InDesign:

https://www.rockymountaintraining.com/adobe-indesign-setting-and-removing-defaults/

Align to baseline can be a little tricky to disable because it is activated either by a paragraph level control or by a text frame control. Since you said it is appearing with "each text box I make" I would start by deslecting all in one of the problem documents and disabling it in Type > Text Frame Options > Baseline Grid > Use Custom Baseline Grid. If that works, close all files and repeat the process without any files open. 

If it doesn't, please come back and let us know.

~Barb