Punitive treatment of the unemployed is usually justified in terms of the incentives it provides. So, for instance, the rationale for increasing the wait until you can claim unemployment benefits from 3 to 7 days is apparently that it “send[s] the message from the very start that rights to benefits are conditional on the requirement to search for work”.
One particular argument made is that unemployment benefits in general stop people searching for work. That’s most frequently heard in the context of long-term unemployment; it is, for instance, at the heart of the myth that welfare policy needs to tackle the problem of households with “three generations of worklessness”. If welfare queens are languishing on unemployment benefit, content to be paid by the state not to work, then cutting that benefit will encourage them back into work.