Well Malta did carry out a push-back. Once upon a time way back in 2002.
Being very eager to be populist the EFA government repatriated 220 Eritrean citizens. These ended up imprisoned and tortured.
You may wish to read through the correspondence between Amnesty International and the then Minister Tonio Borg at the following link:
These are the consequences.
Blog ta' Carmel Cacopardo 
It took Great Britain over 10 years to deport Abu Qatada a condemned person back to Jordan due to human rights charter clauses. Malta obviously is above having to comply with the same EU Human Rights charter. To be fair, as a result of having to comply and delay the deportation of Abu Qatada, Britain is considering opting out , BUT first the Complied with the Human Rights Chartered, even persuaded Jordan to change their Laws on Torture to comply with the EU Human Rights and never therefor broke the Laws as seemingly Malta did then and is threatening now. ( My reference to Abu Qatada’s case does not infer his guilt or innocence – simply demonstrating even the Great Britain governments complied with the Human Charter thought they may feel it was unfair, they first complied in full at much costs and trouble before considering opting out.
It was not “pushback” but forced repatriation. In fairness, the Eritreans did not seek political asylum for some reason that I have never understood. Moreover, at that time, the prime minister was Fenech Adami. The only case of “pushback” was indeed under the Gonzi government in July 2010 when the migrants on a boat of distress were split up, half of whom were brought over to Malta and the other half sent back to Libya on an Italian vessel.
http://www.alexcutajar.com/2013/07/hypocrites-watch-this.html
Referred to your article, and added another one.