HELP ME UNDERSTAND SKIM COATING

Here's an example that was all over the car. The fender in the pic was clean and showed no signs of repair pre-accident. LOL.....After attempting to clean the panels, and subsequently giving up, this colour makes me ill just looking at it:)
I'm guessing this is an example of what a shitty body job looks like. They probably used way more than they had to.
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