Was Tywin justified in killing all the Reynes?

[Lord Freypie]

1 hour ago, Trigger Warning said:

They're not going to accept any offer that doesn't involve hostages for fear of exactly what you're saying Tywin should have done instead. 

I may admit there was little chance to see them settle for a surrender with no guarantee, but out of the fact Tywin didn't even try to obtain that, it was also his fault if you don't start the story at the Castamere siege.

I mean in his short campaign, Tywin had already executed the Tarbecks prisoners of first battle (not even trying to use them as hostages to obtain a bloodless Tarbecks Hall surrender), all their relatives after taking the keep, etc..

Through Kevan he made one surrender offer to lady Tarbeck (exact terms are unknown), but no matter how generous they were, considering her husband and two of her sons heads were on pikes at this point she was unlikely to believe in his mercy.

And naturally, after he took Tarbecks Hall, burned it and killed all the family (minus 2 or 3 women turned into silent sisters), the Reynes (lady Tarbeck brothers) were as unlikely.

Basically asking only the question "was Tywin justified in killing all of the Reynes ?" and considering the siege situation, is taking the most favorable moment to find him excuses.

He had perhaps one to be that ruthless, the fact his father was likely to disavow him and pardon his enemies if he spared them (like he did after the first Reyne-Tarbeck rebellion).

But considering his father was a weak man, there's as much reasons to think he would have bowed to a strong son than to strong vassals imo (especially after his son would have proven these vassals weren't that strong finally, and he had support from many others)

Starting from the beginning of the conflict, he could have chosen a different path still showing strength but not unecessary one :

 - execute lord Walderan Tarbeck as the one who decided to take arms against his liege, to show he meant business, but keeping his two sons as hostages

 - (at least try to) obtain bloodless surrender of Tarbecks Hall for their lives, with as bonus conditions Elyn taking their place as hostage (to paralyze her brothers), and the repayment of the debt he was asking for in the very first place (he finally never obtained as he just destroyed the in debt families, not really pragmatic from M.Pragmatism)

(to obtain that he could even have done like Jaime at Riverrun, as one of the prisoners was the heir, releasing him so the die hard old lady Elyn wouldn't have been in command of negociations, but someone having a future to lose)

 - being inside Tarbecks Hall, with Elyn and her family at his mercy instead of dead when lord Reynes arrived, he would have prevented the second battle, and would have been in a far better situation to obtain favorable conditions from them than sieging their unconquerable seat after injuring their lord (one more time getting the gold that he was supposed to ask for)

 - finally returning home with the prestige of this double quasi bloodless  victory, and an army supported by strong families like the Marbrands, make his father realise he was the strong man to fear in the Westlands not the Reynes and abandon any involvment in politics