Otters are no different than deer, Canada geese and many, many other species.
You can add all of the problems various species have together and they won't equal the damage caused by deer. The costs of accidents caused by deer, damage from deer eating crops and plants around houses and then Lyme disease are staggering. Obviously, we should get rid of all deer!
However, there are benefits of having deer and all of these other species also. Everything is a balancing act.
Trappers consider otters to be a economic benefit. People that pay money to view otters in the wild contribute in a big way to the economy. The damage occured by a few is insignificant compared to the economic benefits enjoyed by many. That is unless we happen to be the ones suffering the damage. This can be said for many other species.
We already know how to handle all of these problems. First, we try to separate the problem species from our areas. Second, we try to use non-lethal actions such as dogs etc. Lastly, we target individual animals that are causing problems. When we don't follow these steps, we often end up with more problems than we started with.
These are the types of controversial subjects that we need to be addressing. I hope that I'm presenting these ideas appropriately because I mean no offence to anyone.