==Got the same thing in Poland.
Poland bans small parties and independent candidates as well?
To get into Sejm (Seym - Polish Diet or Parliament) you must have at least a certain percentage of the votes.
The purpose is to eliminate smaller parties. In proportional system of voting it is needed in order to prevent chaos and frequent changes of government. Similar tresholds are in Italy, Germany and other countries.
In countries with majority voting (USA, UK) even the third parties (not speaking about the forth of fifth) have great difficulty to enter the parlament. Fixed minorities are not represented at all unless they are segregated geografically (like Welsh in UK or blacks in some US districts). With majority system of voting you do not need tresholds to eliminate smaller parties.