All refugees in detention are political prisoners

Dear Prime Minister,

Today, Melbourne's port was blockaded by protestors. Their banners included 'SOS Manus' and 'All refugees in detention are political prisoners.' How much did today's port blockade cost Australia's economy? On financial cost alone, how can you continue to allow the offshore detention of refugees?

Do not reply with the platitude 'We need to stop drownings at sea.' It is immoral to imprison and torture  the 2000 people on Manus and Nauru on the pretext of preventing other people's suffering. The boats have continued but the Australian navy now intercepts them (at vast expense) at sea and illegally and secretly turns them back. Last week, a boat with 29 Sri Lankan adults and children reached Australia's shore, which disproves your claim that no vessel has arrived for 3.5 years. Did the Sri Lankans claim asylum? If so, why were they flown straight back to Sri Lanka? How much did that 'special' flight from Exmouth cost?