Technically this is not advertising as he is telling the applicants the server that they need to go on if they wish to be a trial for the build team. Their server is of no threat to MCGamer as it is a private build server.
'7. Do not advertise: Advertising other communities or events in order to profit is prohibited.'
This build team does not earn any profit from their server and it is not part of a separate community. Therefore, it does not violate this rule.
Sorry for any confusion here -
chockadlad maybe PM them in future?