I'm not sure what you mean by "prevent". A TOS is a legal document designed to put down rules and a legal basis for the service.
I don't know what a "guild" is, if it's some Discord thing, and you don't say whether this is a good-faith human who joins, or a bot operator, intending to scrape. The hypothetical is irrelevant here; what is germane is that the expectation of privacy by the individual participants, and the terms which bind people who use that service.
The TOS clearly didn't prevent the use of API, but it may indeed prohibit such scraping, or threaten repercussions for people who break the terms, especially for someone who republishes the data. Your example of a simple download dump doesn't seem to involve republication, and that seems to be the major issue with scrapers.
I don't know what a "guild" is, if it's some Discord thing, and you don't say whether this is a good-faith human who joins, or a bot operator, intending to scrape. The hypothetical is irrelevant here; what is germane is that the expectation of privacy by the individual participants, and the terms which bind people who use that service.
The TOS clearly didn't prevent the use of API, but it may indeed prohibit such scraping, or threaten repercussions for people who break the terms, especially for someone who republishes the data. Your example of a simple download dump doesn't seem to involve republication, and that seems to be the major issue with scrapers.