I don't see anyone here making a distinction between selling boosts directly for real money on discord or elsewhere (against the rules) and selling boosts for gold (not strictly against the rules). That's BS of the highest order. Blizzard is not taking a side on where the gold comes from (unless obtained illegally) but very much is taking a side against boost selling for real money.
There's also the issue of guilds acting as escrow services for boosts which is very much against the rules.