Some people are very badly affected by polyamines, while others can consume them with no obvious problems. I doubt they're particularly *good* for anybody, but some individuals can consume frozen foods without problems- and in many cases, frozen foods are the best or only way to get compliant foods out of season, or make it possible to buy healthy foods in bulk and freeze until needed.
Wild caught fish is definitely a healthier choice than farmed fish. I can't find any non-farmed, certified kosher fish, so I don't buy fresh fish. I get a lot of good quality canned fish.