My question is that what is difference between Khilafah and Malookiyah and why is Hazrat Ameer Muawiyah (rta) mostly blamed for that. And is Hazrat Muawiyah really responsible for turning Khilafah to Malookiyah?
Khalifa is a word that was used for people who became the rulers of Muslims after the demise of the prophet (pbuh). Literally it means one that stays behind, successor.
While literally the word Khalifa can be used and has been used for any Muslim ruler who became head of the state of Muslims in the past (when Muslims only had one state), the word Khilafah, that is an infinitive word, sometimes refers to the system where the Khalifa is elected by representatives of people rather than by means of inheritance.
As opposed to this, Malik means king and the word Mulukyah is used to refer to the system where ruler-ship is inherited and is normally taken by one of the sons or relatives of the previous king.
With the above definition, obviously the first 4 rulers of Muslims after the demise of the prophet (pbuh) were running a Khilafa system, while the rulers after them can be said to run a Mulukyah system.
Based on reports, the first 4 Khalifa had no intentions to make their sons the next Khalifa. This is while the 5th (or if you count Hassan - ra - as Khalifa), the 6th Khalifa, i.e. Muawiyah, based on what we read in historical reports, made sure that his son will become the ruler after him. This practice then continued among the rulers after and this is why the ruling system that started from Muawiyah was called the ruling of Bani Umayyah, simply because the ruler-hsip continued in that clan and that generation. Once the ruling of Bani Umayyah ended, a different clan, i.e. Bani Abbas started the same system in a different generation.
Mulukyah system is not in accordance with the directive of the Qur'an where it says that the affairs of Muslims (which definitely includes selection of ruler) should be based on consultation.