♻️ Replace logger.error; sys.exit pattern with raise SpecificException pattern

[shnizzedy]

Where I came upon the pattern:

print(error_message)
sys.exit(exitcode)

, I wasn't consistent. Mostly I updated to something like:

logger.error(error_message)
sys.exit(exitcode)

but sometimes I did like:

raise Exception(error_message)

(but with a more specific error class than Exception). I think we generally want to convert all the sys.exits to raise Exceptions, but this PR's already uncomfortably large without doing so. I think that can be a subsequent PR if we care to.

Originally posted by @shnizzedy in #2062 (review)