Back from long weekend. My apologies I just assumed it was a dot com.That url is no longer active, so if you have another source I would be happy to look at the evidence that small concentrations in salmon are not harmful. My understanding is that as long as you keep your consumption down then the accumulation over time should be low. How low is safe is not clear to me so if you have a link I would be interested in reading it.
https://salmonfarmscience.wordpress.com/library/
Now I understand this will get flamed as propaganda by some folks - I get it. I don't have the time to post links on this particular topic, but do know that the individuals from this site have posted reports on it. However, I will say that unlike Morton's blog, the site I posted does should a variety of reports - not just what is favourable to their point of view. So you will find the Hites paper in their references.
If you really want to get down to it there are many things that if consumed in high quantities can be potentially harmful. However, many would have to be consumed in such high quantities in such a short period of time that the person will likely vomit before being severely impacted. If the concentrations of contaminates in farmed fish which are extremely low to begin with are still too high for some folks they can cut off more of the fat. But in my opinion, there are far greater risks to public health and for me this doesn't pop up on the radar.
Sugar is more of a threat. Saturated fats are more of a threat. Processed foods are convenient and not bad sometimes, but not all the time. Eating fruits and vegetables is important. My kids love fruit juice, but they don't get any until they eat their fruit and they only get juice once a day - not a Frank-the-tank funnel system from the top of their heads with Sunny Delight. Making sure that fish is on the dinner plate one or twice a week (Just so you know I primarily fish for trout and get my kids to catch and eat trout. I don't get much from the store, but I don't knock those that do). This is what guides me and my dietary choices for my kids, but to each their own.
I understand that for some folks consuming farm salmon is just totally unacceptable because they feel it's unhealthy, but when a website like the one posted at the beginning starts criticizing farm salmon because of tapeworms (as if wild salmon have none) I just have to laugh. Here is a common parasite found in wild Pacific salmon that many salmon anglers may have seen.
https://fishpathogens.net/pathogen/henneguya-salminicola