While I feel that SO or SE helps people especially programmers and sysadmins to get knowledge on things they really need to do or work on I tend to feel the down votes, regulation of questions and answers, harsh words thrown to newbies tend to make it dangerous as you grow from a new contributor especially at the moment. Don't you think SO should be considered as both dangerous and helpful just like other social sites to help people with questions to ask them without fearing to get whipped with down votes or strong words.
I think you're misinterpreting the whole goal of Stack Exchange. Each site is meant to be a high-quality library of questions and answers. It's not "dangerous". Yes, we do downvote and close questions sometimes, but that's only to keep the quality of the site high.
When in doubt, you can refer to https://meta.stackexchange.com/help/on-topic and https://meta.stackexchange.com/help/dont-ask for the relevant site. If you disagree with the closure, you can cast a reopen vote when you have enough reputation or ask about it on meta.
So, no, Stack Overflow cannot be considered both dangerous and helpful. We only use downvotes for bad questions, and harsh comments can be flagged. But most comments are to help you learn how to use the site, not to make you hate Stack Overflow.