any govt. agency involved in intell and interior security be it ISI, CIA, Mi-6, Mossad, RAW, the KGB in soviet days will continue to and have crossed the so called 'red lines' of state laws and have conducted ops which are sometimes authorised and many times not and by mind-set are not expected to be answerable until they get exposed by a 'whistle-blower'. the organisations are secretive in nature, their training such that they eliminate the target first and ask questions later. - their actions may shock and apall many but to some it is quite necessary in this murky and shadowy world which many do not understand (esp. our self righteous media) they serve a purpose for their govt / bosses and we are not aware of the 'real' stories reasons behind these actions.
There are a few fundamental flaw to the logic of towing the line that "America does it, too!" - consequently the same line that Gen. Kayani used here.
1) America is not so bad at doing it. They don't get caught even if they do by their own legal system. Because if they did, there would be no escaping their own law. Presidents could not escape their law, CIA is nothing. All CIA torture facilities are in foreign countries
2) They act against foreign nationals and go out of their way to protect their own nationals. They go through great pains to build a case against their own nationals. They make sure crime scene investigation is done properly, they collect all sorts of evidence and then nail them in court. There is no ISI like "We said they are terrorist, so isn't it enough?" type arguments in their courts.
3) You're aspiring to be something wrong in the first place if you know America does something wrong, why aspire to be something wrong?
In most countries where agencies, law and executive authorities get along is where they have all kept processes, regulations and laws, supreme, more than the agencies, more than the Chief Executive.
The rumors that CIA assassinated Kennedy are alive till today and CIA still hasn't been able to wash their hands off that. CIA made 1001 attempts to kill Castro - who cares about that in America? CIA came to Pakistan, violated all sorts of international laws and killed Osama Bin Laden and took off with his body who in America cares about that? But yes if they kill Presidents, people do care about that, they can kill a thousand Osamas, but it won't justify them killing a single American.
There will be no one in America who will agree with you if you decided to give any agency the right to kill Americans without trial. In Pakistan you're arguing this right to be given to ISI, why?