Salauddin's action after Hattin

I have always been a little confused by salauddin’s action of killing all the captured templers and hospitallers , but apparently not other captured chrisitan soldiers after his great victory of Hattin.
Obviously i dont mean to say that the knights were lillyfaced innocent choir boys either
Killing occasional criminals after conquest [which he did with raymond] DOES have a precedent in Islam
Prophet did after fatah Makkah
Umar’s time after battles of Jahula & Madain some accounts say injured commanders were finished off
Ali’s time a prisoner who had killed the sahabi zayd b suhan in battle,was executed after capture

But what is the precedent for slaughtering dozens of captured fighting men in islam ? simply because they belonged to a particular military order
In all above cases from Rasool and khulifa the criminals were punished for their individual actions but saladin’s action seems like collective punishment …
it is all the more surprising as saladin by all accounts was extremely generous to friends & foe alike and never mutilated or tortured his opponents like zangi]

please give any example from lives of Prophet or pious caliphs which saladin could have used as a precedent

Re: Salauddin's action after Hattin

The punishment of the Banu Qurayza comes to mind...although that may well have been self inflected on their own part as they chose their own arbitrator...

In the case of Salauddin, if he feared trechery he may have had no recourse but to slay them all. Of course, there's always the possibility of personal vendetta! But given his record, I suppose we can presume there was more context than what history records....

I thinks it is related to avenging for the Hajj caravan enroute to the holy sites which had been raided and slaughtered to the last man, woman and child by these very 'templers and hospitallers'

Thats what i thought too but
in case of banu qurayza they committed treachery and according to jewish law its punishment was killing of men and enslavement of women & children plus this was pronounced by sa'd b muadh a sahabi who was an ally of banu qurayza. as you have mentioned]
I agree that in terms of oridinary statecraft this was a neccesary act esp since the knights gave no quarter to muslim soldiers who surrendered.And one of the knights raymond [forgetting last name] allegedly raped saladin's sister

i didnt know that , if thats the case then its a new situation which i dont think the caliphs /prophet faced

in this way one example close to this is bilal killed his master ummayyah AFTER he was captured in Badr [but again an isolated incident]

Raynald of Chatillon

Some detailed info: NationMaster - Encyclopedia: Raynald of Chatillon

This was falsely spread by the christians to sully the name of Salauddin as if he did that to take personal revenge.

Re: Salauddin's action after Hattin

^ well I trust ibn-athir for the most part , so maybe this was a piece of medevial propoganda
but as i mentioned before killing raymond was justified by was the mass killing of all knights of military order after they surrendered ?