I agree that the Soviet made Kilo subs are reasonably effective and modern submarines that could pose a significant threat if treated lightly.
However, I'm talking about the indigenous submarines Iran has been building since the mid 1980s based on imported North Korean technology. These subs are almost certainly slow, noisy, and have very limited sensors. Iran also makes torpedoes (supposedly) and several kinds of mines.
I don't think these subs are a "joke" at all. They are, however, relatively unsophisticated and probably don't have the ability to launch anti-ship missiles (such as the Exocet or Silkworm) as suggested in the article. Any indigenous "missile" launched from that pod mounted forward of the sail is going to make the sub far more vulnerable than if Torpedoes or mines are employed.
Sweden has several small submarines. They rejected the use of missiles such as Harpoon for that very reason: Launching the missiles in confined waters (Baltic or Persian Gulf) would quickly give the sub's position away.
Ok this just a thouht..but what if they can mass produce these small limited use subs like the Japanese dis in WWII the use them in the gulf as a "wolf Pack to attach shipping. Also how big are these things? From what I could see they are fairly small..could they be placed in a Cargo Container. Imagine a few of these launched just before it's Mother Ship makes for port. As I said just a thought....