It's an exaggerated meme. Custodian guards are about 45 points each (and since they have their guardian spears, they're not costing more for sentinel blade + storm shield). They may have their +1 pts daggers, but that doesn't increases too much their costs. Captain Tragg's about 150 points.
One of those big boy knights costs more than this entire Bananaboy army. Though we may ask how much his cardboard cutout of a fucking PNG costs pointswise

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Also, I saw a friend field his orks infantry vs a chaos knight player, and I never seen a player get tabled so quickly. Did you know that chaos knights don't have invulns? Power fists just fold them in half it's not even funny.