Of course, I am the one with the problem. Community norms differ, and if you arrive with different norms, failure to meet your expectations is your problem, not theirs. “Impolite” is a culture-relative term.
If most lower-level instance runs have been “level 80 plus 1-4 alts” for the past year, it is perfectly reasonable to expect that someone is going to do it for you. The group leader might be amiss in putting together anything else without warning people. If you receive a tell with two to four characters and a question mark, your interlocutor might reasonably expect you to recognize that as an invitation to a specific instance, zone, or quest line.
I find it annoying and rude that people use the trade channel for guild recruitment when there is also a dedicated guild recruitment channel. I am obviously at odds with the norm, because I have never seen a single message on that channel. Realistically, one channel will absorb almost all the discourse no matter what it is labeled. In City of Heroes, it was our badges channel; in The Lord of the Rings Online™, global looking for fellowship. Whichever channel has the most people will have the most chatter and attention-seekers, so it should not be surprising to see a trade channel filled with discussion about who sucks.
Announcing what items you just put on the AH, though, you’re obviously a screwball.