There are indeed extremists in most religions, and I don't like those either. But I don't think they are the majority in any religion, and I'm not sure that banning all religions to solve the problem of extremism is fair or proportionate, when that would mean taking away something that is a source of comfort and meaning to so many other people.
As an atheist, I value being free to believe what I believe. And I value that same freedom for people who have different beliefs to my own - they should be free to believe what they believe.
I don't necessarily disagree with you that many religions started as a form of control, threatening people with God's wrath or eternal damnation etc if they don't behave in certain ways. I don't like that approach at all. My mother grew up with a very "fire and brimstone" version of Catholicism and I think it was very damaging. But at the same time, I don't think those models are representative of all religious thinking, and there are many much more moderate people - and institutions - which interpret things quite differently.
I'm sorry that you had a bad experience in the area where you lived previously, but I don't think it's valid to extrapolate from those experiences to make assumptions about Islam as a faith or all Muslims. I've known lots of Muslims over the years, both here in the UK and when I lived for a while in a predominantly Muslim country. There have been some that I really didn't like. But equally, there have been some wonderful people who have become dear friends.
I'm not saying that religious extremism isn't an issue. Of course it is. If we look at what's happening in Afghanistan, for instance, it is utterly abhorrent - but all of my Muslim friends think that as well, and it doesn't represent their interpretation of their religion in the slightest. And yes, there will be people who think that terrorist atrocities are ok or even desirable - but again, such views are as abhorrent and incomprehensible to most Muslims as they are to me. Just as very extreme Christian fundamentalist views are abhorrent and incomprehensible to most Christians.
Personally, I don't think banning religion is the answer. Instead, we need to try to understand why people get radicalised and adopt those extreme views, and then we need to tackle the root causes of that.