The contrast between the whole site, its pupose, its target audience and so on and the contents of the article is almost ridiculous. These words are indeed the actual swear words. But you should never use them. It's not like f-word in English, which is used very loosely though most likely will be beeped if it is a TV show. No. These are very strong, very harsh words. Probably like a c*nt-word for Americans. I can not imagine a Russian who has learned any foreign language and still use such words when he speaks Russian. It's just different kinds of people. One can say them and another one is willing to learn something. They don't overlap.
Though I must admit that the whole article and especially the sentence "Generally, adding “suka, blyad” to the end of each sentence is a good way to master swearing in Russian" made me laugh, because it is so true.