In the name of Allah, the Most Gracious, the Most Merciful,
When using the expression "one of ... ", the verb used is singular because it refers to a single object from a group of objects.
One of the things that I learnt in school was there are just some people you can't stand.
One of the students insisted that I was wrong. It was funny because if I was* really wrong, why would only one student realise it? What about the others?
Observe the underlined verbs. The verbs used are singular while the subjects are plural subjects. As mentioned earlier, the verb is singular because when we use "one of ...", we are actually referring to a single subject and hence the singular verb.
See? I do update my blog.
Allah knows best.
*edited after comment by H