The comparison is bad, but you'd need to at least compare non-bettors to people NOT participating in the meme stock mania.
There are millions of people out there betting on BYU to win games and beat the spread. Perhaps you can't imagine someone betting on a team they don't routinely cheer for, but that is 99.9% of sports betting.
Again, the fact that BYU doesn't beat the spread more often than other teams whose fans have a higher propensity to gamble proves your theory is wrong, but you keep doubling down.