Sometimes people buy products that are not as good as what they had before, especially with power filters -most power filters don't sound as good as plugging straight into the wall. Some are better and it does depend on how bad the current is from the wall.
Some power filters are like a bandage. If you have a wound, a bandage is a good thing. If you don't have a wound, a bandage is a bad thing.
Uhh, so... A lot of power filters make the sound worse, but it makes a change. So, if the attitude is "change is good," then yes, somebody might put in this thing that makes it sound worse, but in that moment, the change is the permission to stay up all night, rediscovering your music, because the relationship is new. Then, a year later, they take out the filter and they say, "Oh, how could I ever live with that?"