So just because one person is cheating, it means all academics are cheating?

FWIW, most top-ranked CS conferences have an artifact evaluation track, and it doesn't look good if you submit an experimental paper and don't go through the artifact evaluation process. Things are certainly changing in CS, at least on the experimental side.

It's also possible that theorems are incorrect, but subsequent work that figures this out will comment on it and fix it.

The scientific record is self-correcting, and fraud / bullshit does get caught out.