In theory..Is it wrong to pick the right honest good people
Do you suppose those wanting to work in the UK would put "dishonest rapist thief" on their CV?
I'm not sure how the two parts of your sentence fit together or whether you are asking two separate questions.Is it wrong to pick the right honest good people and not let big businesses use them as cheap labour.
The reality is big businesses and small businesses will take advantage of vulnerable immigrants. All the rest are entitled to minimum wage or better.
None of the above will be solved by leaving the EU without a deal.