Ramadan section; I need help understanding some of the suras that are in the quran.?

we all know that males being alone with single females is forbidden. so explain these. sura 4:24 all married women are forbidden unto you, except those captives whom your right hand posses....sura 70:29-30 and those who guard their chasity [ie private parts from illegal sexual acts] except with their wives their female slaves and captives whom their right hand possess, for them they are not to blamed. they are dozens of suars and hadiths like these..so being that muslim men can't be alone with females. do they have to rape them in public