I can see the no trade via pm rule (lots of trades go on in poe2 and even Poe on its release year via pm! Must be a culture thing) but the hijacking the thread I see none of it on the thread we were talking on, again good luck bro and here's to hoping to a prosperous future!
You can't see it as he just pm the people in there.
so someone offers me 50 div and he straights away sends a link this via pm "@xxx Hi, I would like to buy your Glyph Vessel Sapphire listed for 50exalted in Standard (stash tab "Trade"; position: left 4, top 1)" that is then used by the seller who then pm him ingame.
If you can do this what are the points of making threads and bumping them each 3 hours if you can just go into other people threads and pm the people there? And just stealing the trades from the trade owner. This is also a way to scam. A fresh account can go into existing trades and make the same pm, and maybe the seller dosent realise its another person. That is one of many valid reason to trade via threads and no pm.
A 3rd user also confirmed to me that chowmiw approached someone in his thread, where chowmiw said he was the threadowners friend and would make the trade.
Basically this users is trying to get as many divines as cheap as possible and dosent care how he does it. No manners what so ever.