You should start your own thread instead of hijacking someone else's with a completely unrelated question.
The short answer to your question is, no, it's very unlikely that you can successfully claim humanitarian or compassionate grounds, unless you're from a country that is currently in a state of war, or something equally serious like you face some kind of persecution from the government if you went back home.
As far as your age, I'm not sure where you got the idea that you can't re-apply just because you're 51. That's simply not true.
Under the Federal Skilled Workers Program, age is just one of the factors that they consider and give points for. The maximum number of points you can get for age is 10 points, and that's for people who are between 21 and 49 years of age. If you're 51, you would still get 6 points. At 52, you would get 4 points.
Other points categories are far more important, such as education (maximum 25 points), English skills (maximum 24 points), work experience (maximum 21 points), and then two other categories of having arranged employment in Canada and adaptability (maximum 10 points each). So as long as you're able to get a passing mark of 67 points, there's no reason why you can't apply again.