They really aren't. Honestly most banks don't care what "illegal" things you do as long as you give them plausible deniability.

If you cause the bank more problems than you do bringing them in money, then they're more likely to ban you. Even in this example they're stating that you shouldn't use these words, just that they are required to investigate these words.

Also if they genuinely thought you were performing illegal activities they wouldn't tell you, they would had it off to the proper cover your ass department.

That being said, don't actually test what words bank monitor, since, as I mentioned, if you're a pain in the ass on purpose they'll probably drop you, or at the very least freeze funds for a long time.