That is the stereotypical view of many Indians who have little understanding of Pakistan. Pakistanis are not subservient to their religion, they make their religion subservient to Pakistan. Pakistan started to play up and use their Islamic identity in the 1970s simply because they had nowhere else to go. Bhutto saw that Nehru had taken India on the world stage and become a world leader by forming NAM (Non Aligned Movement). Bhutto wanted to do that for himself and Pakistan, and not having any other platform, he decided to rake up Islam and try to become a world leader in the Islamic world. That is when he went rabid and started mixing his Socialist policies with Islam. It is also when Pakistan started playing with the "Islamic" bomb (not Pakistani, but "Islamic"). When Zia came onto the scene, he again tried to use Islam to try and serve Pakistan's interests by shaping Islam into an anti-India tool and trying to forge a Pakistani identity on that basis. He revamped the whole education system to brainwash Pakistanis with such propaganda and lies, and which is today the base of many of the educated but deluded Pakistani youth of today. If you talk to the older generation of Pakistanis, ones educated prior to the 1980s, you will find a world of a difference between them and today's Pakistanis. The older generation of yesteryears is much much saner and not as deluded.
So, it is very flawed to claim that Pakistan is built around Islam; actually it is a very humorous joke to state that. Pakistan has not built itself around Islam, they have built Islam around itself and to serve Pakistan's national interests.