I did not read the whole article but yes fish oil in high doses can be immunosuppressive to T cells.
This has been known for a long time.
Some fats are inflammatory and others are anti-inflammatory.
More disease and pathology in this country are caused by too much inflammation. A generalization but most things that decrease inflammation may to a certain extent decrease immune response. I get sick enough to miss work for 1 day about every 5 years on average, so I am not concerned about a very mild decrease in my immune system. There are many others that have never missed a day of work and yet die of terrible health a few years after retirement so this logic is not entirely valid, I admit.
I take very high doses of fish oil about 12- 20 pills most days. I have a good medical knowledge and know the pros and cons and reevaluate as more knowledge comes in.
Telling everyone to take fish oil is great, but when it comes to very high doses or mega dosing one should know the facts before they make this decision. I tell most people that ask me about fish oil to try taking at least 4 fish oil pills but most do not even do that.
My definitions. 1-3 pills of fish oil is low dose. 4-12 is moderate. 4 Prescription fish oil pills (most common dose) equates to about 12 1000mg pills (180/120 EPA/DHA) daily of most good fish oils at usual doses. Beyond that to me is high dose. Beyond 20 pills or 1 pill per day per percent of body fat if obese to me is mega dosing. If fish oil is really proven someday to do more bad than good than I will stop taking it, but I doubt that this will ever be proven. If one is really eating wild salmon of fatty fish regularly they need to consider this as a source of fish oil also.
Keep in mind very few things have actually been proven to extend life expectancy beyond antibiotics, general improvements in public health, and possibly sever calorie restriction (no thanks). Hell, even one of most prescribed and researched type of drugs in the world, the Statins, have had serious research to question if they are more than very, very slightly effective for the most at risk patients, and yet carry known side affects.
I also take coconut oil in moderation daily. The dangers of coconut oil have been way over exaggerated but many of the health benefits have also been exaggerated. Meaning most of the benefits have yet to really be proven beyond a reasonable doubt by any really good studies.
The number one thing people can do for their overall health period is to have good insulin sensitivity. Of course, to have this you must be lean, active, have a good diet, good genetics, and certain supplements can help to a lesser extent such as fish oil. Basically you need to have the opposite lifestyle of those with metabolic syndrome. Starting to ramble I will end here.