The main problem is that any evidence released promptly or later, will always be refuted in some way by Pakistan in their eyes.
After all how many Pakistanis still believe Mumbai was a "false flag" or whatever....in opposition to all major world intelligence agencies.
So might as well release at the time and place of our choosing....if we even really want to (beyond what might be leaked inevitably)
This also helps Pakistan to deny and ease the stabilisation process. This is what India wants too.
You have to remember India primarily cares about India and izzat for her forces....not forcing Pakistan into a corner with little options as well. We cannot create the undeniable conditions like in Dhaka for each clash there is.....given the very nature of the majority of these clashes....of which Kargil is arguably the largest in post nuclear south asia.
I can fill your head with all kinds of parallels that the Israelis and Arabs did in the mid 20th century regarding this kind of conflict....and how each side simply didn't care proving anything to the other side, as long as "results" were achieved as they saw it...and credibility was established in their populations first and foremost.