Mot likely it was deleted by one of the moderators, yes. As to why, I can't say for certain, but my first guess is that the conversation was straying toward dubious activity regarding copyright and licensing. This isn't allowed, as explained in the Forum Guide
. Even though it may not have been your posts which were deemed inappropriate for whatever reason, the topic likely got deleted.
The one who did the actual deleting could perhaps offer a more specific explanation.