This first part is fairly irrelevant to pvp…
When a website advertises that they sell attempts at the lego from the raid or any number of boss kills from the raid, and anything else in game, Blizzard cant know without quite a lawsuit who actually owns the website. Blizzard will likely never know who carried the sold raid spots or who bought the raid carry and subsequent gear.
Pvp carries can also be bought/sold as RMT on the same or similar websites, but the sites remain. Either Blizzard cannot take legal action on the sites and providers and users, or they choose not to.
In either case, I could not care less if basic bob buys the Lego Axe(as many attempts as it takes through Heroic last boss carries) for $1800.00 USD.
What negativly effects BGB and Regular BG gameplay more so than queue syncers and RMT (however still bad) is just poor design/balancing.
For pvp, some tank specs are tanks, most just die, fast. Some healer specs are livelord gods, others are not much more durable than most dps.
Some specs have most of thier defensives unable to be used if they carry an orb or flag, most specs do not suffer from that poor design.
While addressing RMT, Queue Syning, and general gameplay sabatoge is good, spec balance needs a whole lot of work before it can be a game worth banning people for ToS violations over. Generally pvp is a bad game mode due to design and tuning, and if you are not exploiting it in someway you’re likely having a bad time.
Making the game good enough for players to care about, will take MANY changes and should be a top priority.
With all of the metrics to judge the results of the current game design, Blizzard should know what is needed by now. I’m done telling them.