Is this abuse?
You occasionally see guild recruitment in the LFG which I don’t particularly mind. As long as it doesn’t clutter the LFG panel its generally not a problem. I’ve never seen anyone trying to sell through there which seems like it would be against the rules. Since theres no real trading system it can lead to scamming if players start sending items through the mail.
I have a vague recollection of this coming up before and someone official saying LFG is not a trade chat and using as such would be reportable. Dunno about guild recruiting, though map chat seems to work for that. (Me, I join guilds of friends with RP themes. I can’t fathom wanting to just net in total strangers without even a probationary period to see if they fit. But I know some guilds prize numbers).
Guild recruitment – maybe (technically, yes, but not an overly harmful use of the tool).
Item selling – 100% absolutely a misuse of the tool and should be reported.
Fate is just the weight of circumstances
That’s the way that lady luck dances
If the guild is focused on pugging then using LFG for that is essentially an extension of LFG in a way so yeah, blurry line but not being a problem right now.
Selling, well, consider them on the level of spammers who would use a deceased relatives contact list to send you something about a porn site. Maybe they just don’t know better, but they probably do. Clogging the pipes with unrelated spam isn’t what the tool is about.