Scenarios:
1. Organic attack from disgruntled Kashmiris against occupation and possible settlement of Indians in the name of 'tourism'. Its a possibility but highly unlikely as such operations need expertise that requires professional training/support.
2. False flag from Indian state. It is a possibility and if true then I don't understand what India is looking to gain from such a maneuver. India had gain ascendancy by removal of Imran Khan (most popular leader). Most pro India group i.e N league is in power already who have indirectly accepted Indian supremacy. Pakistan as a state was already regressing. Why interrupt your enemy ?
3. Pakistani generals responding for Indian activity where they targeted key 'assets' in Pakistan and their support for BLA. Also a possibility.
Guardian
In all scenarios, pure hate fueled by Indian media and the crazy nationalistic fervour displayed by Indian society should be eye opener for Pakistan kuen banaya types in Pakistan. This is an old Indian tactic that they used effectively in 2008 after Mumbai attacks where they used their media to create outrage in order to pressurize Pakistan. It worked then because 'terrorism' and 'Muslim bad' narrative used to sell globally during those times. Also, Indian intelligencia residing outside India were congress supporters who were well connected with global news outlets.
Now this 'terrorist' card in not that effective as people have grown tired of it. People are now aware that most countries use 'terrorist' for their dirty work. Some Indians are aware of it as well but they use ifs and buts to deflect. Social media has also made it harder to shape singular narratives.
Indian state would have been better off had they downplayed this incident (if they didn't do it themselves ofcourse). Now with such hate and over a billion people clamouring for war, they have put themselves in a difficult position. Blocking rivers is a zero sum game. Revoking visas and 'isolating' Pakistan in sports won't quench hindutvadis thirst for 'revenge'. Moreover, chatter of war has forced Pakistanis to once again back military which is against Indian interests.
Finally, India has been involved in numerous attacks in Pakistan in last 15+ years. Supposing that Pakistan was involved in this attack, still Indian outrage is unjustified when you have been playing the same game at far larger scale. Conversely, Pakistanis asked questions from their security agencies after train incident but Indians are in a frenzy without any introspection.
Ordinary people on both sides should strive for peace. Everyday Indian Hindu should accept that a country named Pakistan is a reality and their dream of 'ghar wapsi' for 'converted' of subcontinent will bring misery to a lot of people including them. Same goes for ghazwa hind types but they are minority in Pakistan.