Yeah I don't know what the evidence of widespread people trafficking in the UK is. I did read a story a few years back of some east Asian immigrants who died in the back of a truck somewhere in England. Didn't have anything to do with dinghies though afaik.
More to the point, none of the people in the dinghies are traffickers. If we accept that they're all asylum seekers, their means of getting to our country is irrelevant imo.