You have zero rights for guild spam in trade chat. There are in game tools already for promoting your guild, use them. If your guild is advertising in trade chat it isn't worth joining. People will find the good guilds because they are good guilds, good guilds do not need to spam, they have people banging on their doors trying to get in. If you do not have people knocking on your door, perhaps spend more time making your guild worth joining.
I will be right click/report spam every guild spam I see, just like I always have, and will continue to encourage others to do the same.