In actual Discord practice, that clause acts more as a liability disclaimer. They do not actively look for and kill third party clients like, say, WhatsApp. How

In actual Discord practice, that clause acts more as a liability disclaimer. They do not actively look for and kill third party clients like, say, WhatsApp. However they have an antispam with a high false positive rate, which is tuned to almost always produce a non-spam result with their first party client.