My understanding of balanced play in poker is that the best a counter-strategy can is obtain 0EV against the balanced strategy, but that the balanced strategy also actually exploits every counter-strategy which deviates from balanced (it just might not exploit it to the maximum degree).  This seems true from experience and I've heard a lot of other people "confirm" it, but I don't exactly see the mechanics of how this is actually happens.

In Rock, Paper, Scissors, the balanced player actually makes his opponent indifferent to playing every other possible counter-strategy, so what is different about poker to where counter-strategies against the balanced strategy can obtain -EV?

I'll give a hand example that might help my question:

Suppose we are playing a pot in position and we are checked to on a final board of:

QT222r

If our balanced value-betting range when we make a PSB here is 2 Value: 1 Bluff then every hand which beats our best bluff will have a call of 0EV.  Some of the hands which beat our best bluff, however, are hands like T3s and so on, which seem like they should be naturally exploited by a balanced river betting range.  In other words, mathematically we have JJ = T3s = 44 (can somebody confirm this correct)?

If we run the hand from our opponent's perspective though, it seems like he is deviating massively by getting to this river with some of his bluff-catchers (44-55 etc.).  So where does he lose money for making his turn-calling range too wide?  Is it that he got a lucky river card and he'll have to fold on most?  That doesn't seem right either because we'll still be bluffing rivers and 44 will beat our bluffs.

I understand check-calling this river with 44 is massively exploitable, but I'm asking where it's specifically exploited by a balanced overall strategy.