I tried to answer this question, but was not able to because I don't yet have 10 reputation points. I used Google when I had the same problem, and would like to post an answer. How am I supposed to earn points if I can't answer anything?
That particular post was protected by a moderator. The initial question was asked 3 years ago. As a result that the question was never marked as answered, people will still try and offer new solutions. But because of the age of the post and the spam received, the question was protected to protect the integrity of the question.
New questions don't require any reputation to answer them... unless they are protected.
10 rep is not hard to achieve. Stack exchange want people to be involved in the site not just pass by.
Questions are occasionally protected when they get too many non-answers that are either spam, or saying things like "thanks!" or "me too!" The vast majority of questions are not protected, and can be answered by anybody.
All it takes is one upvote on an answer or two upvotes on a question to earn 10 reputation points. It's very easy to do as long as you write clearly and are polite.