FWIW. Ideology could be either way based on that info. People sometimes register for the opposing party as a tactic to vote in the primaries for the weaker candidate (less likely to win). Donating to dems could either mean allegiance to dems or it could just as well be a true conservative who hates Trump (because true conservatives tend to oppose Trump as well over Trump’s disregard for antitrust situations and his sloppy spending). A Trump-hating republican would also likely register as republican to vote against Trump in the primaries.
What I heard is that he donated to a Democrat-affiliated "get out the vote" group on the day Biden was inaugurated. It's true that the donation was to "the dems," but it sounds to me like the motivation could've been dissatisfaction with the voter turnout that resulted in Biden entering office. Maybe he just didn't know that higher turnout tends to favor Democrats...
The donation record has 20yo Crooks' address, not 69yo Crooks' address, so that's not likely. I don't know why $15 makes him a secret democrat, when there's so much more evidence he's deeply conservative. It shouldn't be an issue.