"Ethnical cleansing"? Dear child, there was a different policy towards those Italians who dirtened their hands against locals (Croats, Slovenians...) and towards those that didn't.
Otherwise, if Yugoslavia had as a goal to make ethnic cleansing of Italians, how come that Italians had their partisan brigade (and that was in every schoolbook), that there were memorial plaques (dedicated to Italians that joined to partisans) all over Croatia (Garibaldi brigade, if I remember well), that Italians had and have their TV-station in Slovenia, that Italians had and have their newspapers (and publishing house) and theatre and organizations in Croatia? 
Second, don't mix those who escaped because of their feeling of guilt, or those who knew that they'll be punished (for their fascist activities and crimes against locals) with persons (manyof them Croats) who used opportunity to leave for the West and avoid advancing Communism. Oh, by the way, did Italy processed fascist officials? We've processed all those that collaborated with nazists and fascists (with very severe penalties, death penalty or losing or being stripped of all citizen rights wasn't rare case). Oh, speaking about "cleansing". How many Italians were colonized into Slovenia and Croatia (on occupied and annected areas, on Eastern Adriatic)? 
Do you know for the data, that Italian authorities have brought personnel (teachers, artisans, engineers) from Italy into annected and occupied areas, in order to ensure functioning of system (and at the same time increasing the number of Italians there), becaue the locals have boycotted schools (and teachers and pupils) and work in factories? 
At last, do you know what the term Italo-optants means?