Secular extremism is a paradoxical term; you cannot be a secular and an extremist simultaneously. However, bigotry towards religious groups is a reality and it is the natural response to religious extremism.
The main problem with religious extremism - and it has been highlighted already - is the practice of enforcing your beliefs on others. Unfortunately in this era, it has become common practice among certain groups of Muslims.
A lot of what has been said in this this thread is true for a country like Pakistan, but I think some people are flirting with over-exaggeration and sensationalism to get their points across. Having lived in Peshawar for 25 years, I believe that I'm in a good position to comment on the ordeals of the closet atheists or even the non-practicing Muslims.
Firstly, I would classify myself as a moderately-practicing Muslim. I pray but not five times a day every day, I don't sport a beard (I despise them in fact) and I also abhor the right-wing and the Mullah ideology. However, I have never touched alcohol in my whole life and never will, I mistakenly had pork once in the UK and I regret it a lot.
Personally, I can relate with some of the issues that have been highlighted so far. I'm a pure lefty and I do all the things with my left hand that a right-handed person does with his right hand, which also means that I do with my right hand what a right-handed person does with his left hand.
I eat with my left hand because I see absolutely no justification and reasoning in the argument that we are not supposed to eat with our left, or the reasoning that 'Iblees will dine with me if I eat with my left hand'. When I was a baby, few relatives of mine thought it would be necessary to force me to adopt my right hand as my dominant one, but thankfully my father had none of it because he is also a lefty like me, and eats with his left like I do.
Initially when I used to eat with my left hand in public, my friends and relatives etc. would tell me that it is wrong to do so and bla bla, but once they realized that I am adamant, they have stopped nagging. I have never had any stranger come up to me and remind how I'm sinning by eating with my left.
Similarly, no one has stopped me from urinating while standing, because it is common practice in schools, colleges and workplaces. I live in a neighborhood which is full of tableeghis, and I have never been nagged to the point of annoyance that I should pray 5 times in the Mosque. For many years, I was a Jummah Khan (common term for people who pray the Friday prayer only) but I have not had people knocking on my door to tell me that what I need to pray 5 times a day.
However, if you run into extremists every now and then, they will rub you the wrong way. As I said, there are plenty of tableeghis in my locality and when they are on their weekly gasht (every Wednesday), they do knock on our gates and request us to come and meet them.
Similarly, if you are invited to a wedding with a predominantly right-wing presence, you will probably have a mullah question your decision to eat with your left hand.
Having said that, the impression some people here are giving is that life in Pakistan is hell if you are not a Mullah or an extremist, or at least that is the impression I'm getting from the comments here.
As I said, I'm a moderately-practicing Muslim. I know people who have no religious inclinations and also drink alcohol etc., and they haven't been lynched by mobs threatened by extremists. My father was a bureaucrat and I've grown up in a social class where drinking is very common. I don't know of a single person who has been killed or even threatened because they are not religious.
Obviously it is down to personal experience, but I'm extremely surprised by some of the comments here. As long as you don't run into the Mullahs, the common man is not going to make your life miserable and you can get on with what you do without any problem.