whatever Kurn's personal reasons, it was absurd that they chose such a drastic solution when only A FEW YEARS BEFORE Kurn had witnessed Worf lose and then regain his honor, just as he would the second time.
Kurn twice sought to end his own life, to expect him to simply endure a couple of years of ongoing shame within his society would be unreasonable.
While there might have been a general amnesty after the Dominion War, it make no sense that Ro would remain in Starfleet in any capacity. And if she went into the Bajorian Militia, Starfleet would not want her on DS9 and would strongly request her not to be assigned there.
She simply couldn't be trusted.