It's strange to me that this isn't the emphasis of the article.

I assume the MRL the lowest amount which could possibly cause harm? If so then why does it matter for the rest of the products where the levels are below that?

It could be for potential environmental harm, but then the fact that these are being exported at all should tell you that they're being used, you don't have to test consumer goods.

Their recommendations include this:

>2. Automatically lower all maximum residue levels (MRLs) of non-approved pesticides to the limit of detection to prevent these substances from making their way back onto European plates via a dangerous ‘boomerang effect

But is this scientifically supported?